Patient interface

Abstract

To provide a medical device having one or more of improved comfort, cost, efficacy, ease of use and manufacturability.SOLUTION: A seal-forming structure for a patient interface may include: a patient-contacting surface configured to engage the facial skin of a patient to form a seal; a posterior opening formed in the patient-contacting surface, the posterior opening configured to provide the flow of air at the therapeutic pressure to the nares of the patient; and a support structure extending from the patient-contacting surface to an interior surface of the seal-forming structure, where the support structure and the interior surface form a continuous loop. The patient interface is configured to allow the patient to breath from the atmosphere through their mouth in the absence of a flow of pressurized air through a plenum chamber inlet port, or the patient interface is configured to leave the patient's mouth uncovered.SELECTED DRAWING: Figure 7A

Description

[Technical Field]

[0001] 1 Cross-reference to related applications This application claims the benefit of U.S. Provisional Application No. 62 / 480,059, filed March 31, 2017, which is incorporated herein by reference in its entirety.

[0002] 2. Technical Background 2.1 Technology field The present technology relates to one or more of the detection, diagnosis, treatment, prevention and amelioration of respiratory-related disorders. The present technology also relates to medical devices or apparatus and uses thereof. [Background technology]

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

[0004] These airways contain a series of branching tubes that become narrower, shorter, and more numerous the deeper they travel into the lungs. The lungs' primary function is gas exchange, allowing oxygen from the air to enter the venous blood and carbon dioxide to leave. The trachea divides into the right and left main bronchi, which further divide into the terminal bronchioles. The bronchi constitute conducting airways and do not participate in gas exchange. The airways further divide into respiratory bronchioles and ultimately into alveoli. Gas exchange occurs in the alveolar region of the lung, which is called the respiratory zone. See: "Respiratory Physiology," by John B. West, Lippincott Williams & Wilkins, 9th edition published 2012.

[0005] There is a range of respiratory diseases. Particular diseases can be characterized by particular manifestations such as apnea, hypopnea and hyperpnea.

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

[0007] Obstructive sleep apnea (OSA) is a form of sleep-disordered breathing (SDB) characterized by episodes of upper airway closure or obstruction during sleep. It results from a combination of an abnormally small upper airway and normal loss of muscle tone in the tongue region, soft palate, and posterior oropharyngeal wall during sleep. This condition causes affected individuals to experience breathing pauses typically lasting 30 to 120 seconds, sometimes 200 to 300 times per night. This can result in excessive daytime sleepiness, which can contribute to cardiovascular disease and brain damage. This condition is common, particularly among middle-aged, overweight men, but patients often experience no symptoms. See U.S. Pat. No. 4,944,310 (Sullivan).

[0008] Cheyne-Stokes respiration (CSR) is another form of sleep-disordered breathing. CSR is a disorder of a patient's respiratory regulator, characterized by alternating periods of waxing and waning ventilation, known as the CSR cycle. CSR is characterized by repeated deoxygenation and reaeration of arterial blood. CSR can be harmful due to repeated hypoxia. In some patients, CSR is associated with recurrent sleep arousals, which can cause severe insomnia, increased sympathetic activity, and increased afterload. See U.S. Patent No. 6,532,959 (Berthon-Jones).

[0009] Respiratory failure is a general term for respiratory disorders that refers to the inability of the lungs to take in enough oxygen or exhale enough CO2 to meet the patient's needs. Respiratory failure can include some or all of the following conditions:

[0010] Patients with respiratory failure (a type of respiratory insufficiency) may experience unusual shortness of breath during exercise.

[0011] Obesity hyperventilation syndrome (OHS) is defined as the combination of severe obesity and chronic awake hypercapnia in the absence of any other clear cause of hypoventilation. Symptoms include dyspnea, morning headache, and excessive daytime sleepiness.

[0012] Chronic obstructive pulmonary disease (COPD) encompasses any of a group of lower respiratory tract diseases that share certain common characteristics, including increased resistance to air movement, prolonged expiratory phase of breathing, and a decrease in normal lung elasticity. Examples of COPD include emphysema and chronic bronchitis. Causes of COPD include chronic smoking (the primary risk factor), occupational exposure, air pollution, and genetic factors. Symptoms include dyspnea on exertion, chronic cough, and sputum production.

[0013] Neuromuscular disease (NMD) is a broad term encompassing numerous diseases and illnesses that impair muscle function directly through intrinsic muscle pathology or indirectly through neuropathology. Some NMD patients are characterized by progressive muscle impairment, resulting in the inability to walk, wheelchair confinement, difficulty swallowing, respiratory muscle weakness, and ultimately death from respiratory failure. Neuromuscular disorders can be categorized as rapidly progressive or slowly progressive: (i) rapidly progressive disorders, characterized by muscle impairment that worsens over months and leads to death within a few years (e.g., amyotrophic lateral sclerosis (ALS) and Duchenne muscular dystrophy (DMD) in teenagers); (ii) variable or slowly progressive disorders, characterized by muscle impairment that worsens over years and results in only a modest reduction in life expectancy (e.g., limb-girdle, facioscapulohumeral, and myotonic muscular dystrophy). Symptoms of respiratory failure in NMD include: increasing general weakness, difficulty swallowing, difficulty breathing on exertion and at rest, fatigue, drowsiness, morning headache, and difficulty concentrating and mood changes.

[0014] Chest wall disorders are a group of thoracic deformities that result in ineffective connections between the respiratory muscles and the rib cage. These disorders are primarily characterized by restrictive obstruction and share the potential for long-term hypercapnic respiratory failure. Scoliosis and / or kyphoscoliosis can lead to severe respiratory failure. Symptoms of respiratory failure include: dyspnea on exertion, peripheral edema, orthopnea, recurrent chest infections, morning headache, fatigue, poor sleep quality, and loss of appetite.

[0015] A range of treatments are available to treat or ameliorate these conditions, and preventative treatments for respiratory disease are also available to benefit otherwise healthy individuals. However, these suffer from several deficiencies.

[0016] 2.2.2 Treatment A variety of therapies are used to treat one or more of the above respiratory disorders, such as continuous positive airway pressure (CPAP) therapy, non-invasive ventilation (NIV), and invasive ventilation (IV).

[0017] Continuous positive airway pressure (CPAP) therapy is used in the treatment of obstructive sleep apnea (OSA). Its mechanism of action is that continuous positive airway pressure acts as a pneumatic splint, for example, by pushing the soft palate and tongue forward or backward against the posterior oropharyngeal wall, thereby preventing closure of the upper airway. Because treatment of OSA with CPAP therapy can be voluntary, patients may choose not to adhere to treatment if they perceive one or more of the following about the device used to deliver the treatment: uncomfortable, difficult to use, expensive, or aesthetically unappealing.

[0018] Noninvasive ventilation (NIV) provides ventilatory support to a patient through the upper airway to assist the patient in breathing and / or maintain adequate oxygen levels in the body by performing some or all of the respiratory functions. Ventilatory support is provided through a noninvasive patient interface. NIV is used to treat CSR and respiratory failure in forms such as OHS, COPD, NMD, and chest wall disorders. In some forms, it can improve the comfort and effectiveness of these treatments.

[0019] Invasive ventilation (IV) provides ventilatory support to patients who are no longer able to breathe effectively on their own and may be provided using a tracheostomy tube. In some forms, the comfort and effectiveness of these treatments may be improved.

[0020] 2.2.3 Treatment System These treatments may be provided by a therapeutic system or device. Such systems and devices may also be used to diagnose disease without treating it.

[0021] The treatment system may include a respiratory pressure treatment device (RPT device), an air circuit, a humidifier, a patient interface, and data management.

[0022] Another form of treatment system is a mandibular repositioning device.

[0023] 2.2.3.1 Patient Interface A patient interface may be used to provide a wearer with an interface to a respiratory appliance, for example, by providing airflow to the airway entrance. Airflow may be provided via a mask to the nose and / or mouth, a tube to the mouth, or a tracheostomy tube to the patient's trachea. Depending on the therapy being applied, the patient interface may form a seal with, for example, an area of the patient's face, thereby facilitating gas delivery at a pressure sufficient to disperse with atmospheric pressure for therapy implementation (e.g., at a positive pressure of about 10 cmH2O relative to atmospheric pressure). In other forms of therapy, such as oxygen delivery, the patient interface may not include a seal sufficient to facilitate delivery of a gas supply to the airways at a positive pressure of about 10 cmH2O.

[0024] Certain other mask systems may be functionally inadequate in this field. For example, masks intended for purely decorative purposes may not be able to maintain adequate pressure. Mask systems used for underwater swimming or diving may be configured to protect against water intrusion from higher external pressures and not maintain internal air at pressures higher than ambient.

[0025] Certain masks may be clinically unsuitable for this technology (for example, if the mask blocks airflow through the nose and only allows airflow through the mouth).

[0026] In certain masks, the patient must insert part of the mask structure into their mouth and create and maintain a seal via their lips, which may be uncomfortable or impractical in this technology.

[0027] Certain masks may be impractical for use while sleeping (eg, when sleeping on your side in bed with your head resting on a pillow).

[0028] There are multiple challenges in designing a patient interface. The face has a complex three-dimensional shape. The size and shape of the nose and head vary greatly between individuals. Because the head contains bone, cartilage, and soft tissue, different regions of the face respond differently to mechanical forces. That is, the chin or mandible can move relative to the other bones of the skull. The entire head can move throughout the respiratory treatment period.

[0029] These challenges can lead to one or more of the following: some masks can be intrusive, aesthetically undesirable, costly, poor fit, difficult to use, and uncomfortable, especially if worn for extended periods or if the patient is unfamiliar with the system. If the wrong size mask is used, this can lead to poor fit, reduced comfort, and poor patient outcomes. While masks specifically designed for aviators, personal protective equipment (e.g., filter masks), SCUBA masks, or anesthesia administration masks may be durable for their intended use, such masks may be undesirably uncomfortable to wear for extended periods (e.g., several hours). Such discomfort can reduce patient compliance with treatment. This is especially true if the mask must be worn while sleeping.

[0030] CPAP therapy is highly effective in treating certain respiratory conditions when patients comply with the therapy. If the mask is uncomfortable or difficult to use, patients may not comply with the therapy. Because patients are often encouraged to clean their masks regularly, if the mask is difficult to clean (e.g., difficult to assemble or disassemble), patients may not be able to clean the mask, which may affect patient compliance.

[0031] Masks for other uses (e.g., aviators) may be unsuitable for use in treating sleep-disordered breathing, and masks designed for use in treating sleep-disordered breathing may be suitable for other uses.

[0032] For these reasons, patient interfaces for CPAP delivery during sleep form a distinct field.

[0033] 2.2.3.1.1 Seal formation structure The patient interface may include a seal-forming structure. Because the patient interface is in direct contact with the patient's face, the shape and configuration of the seal-forming structure may have a direct impact on the effectiveness and comfort of the patient interface.

[0034] Patient interfaces can be characterized in part according to the design intent of where the seal-forming structure engages with the face during use. In one form of patient interface, the seal-forming structure can include a first sub-portion for forming a seal around the left nostril and a second sub-portion for forming a seal around the right nostril. In one form of patient interface, the seal-forming structure can include a single element that surrounds both nostrils during use. Such a single element can be designed, for example, to rest on the upper lip region and nose bridge region of the face. In one form of patient interface, the seal-forming structure can include an element that surrounds the oral cavity region during use, for example, by forming a seal on the lower lip region of the face. In one form of patient interface, the seal-forming structure can include a single element that surrounds both nostrils and the mouth region during use. These different types of patient interfaces can be known by various names depending on their manufacturers, such as nasal masks, full face masks, nasal pillows, nasal puffs, and oronasal masks.

[0035] A seal-forming structure that may be effective in one area of a patient's face may be inappropriate in another area due to, for example, different shapes, structures, variability, and sensitive areas of the patient's face. For example, the seal of swim goggles that rests on the patient's forehead may be inappropriate for use on the patient's nose.

[0036] A particular seal-forming structure may be designed for mass production so that one design is compatible, comfortable, and effective for a wide range of different face shapes and sizes. To the extent there is a mismatch between the shape of the patient's face and the seal-forming structure of the mass-manufactured patient interface, one or both may need to be adapted to form a seal.

[0037] One type of seal-forming structure extends around the periphery of the patient interface and is intended to seal against the patient's face when force is applied to the patient interface with the seal-forming structure engaging against the patient's face. This seal-forming structure may include an air or fluid-filled cushion, or may include a molded or shaped surface of a resilient sealing element constructed of an elastomer such as rubber. With this type of seal-forming structure, if the fit is improper, a gap will form between the seal-forming structure and the face, requiring additional force to press the patient interface against the face to achieve a seal.

[0038] Another type of seal-forming structure uses a thin flap seal positioned around the periphery of the mask to provide a self-sealing seal against the patient's face when positive pressure is applied within the mask. As with the previous type of seal-forming portion, poor fit between the face and the mask can require additional force to achieve a seal or the mask can leak. Furthermore, if the shape of the seal-forming structure does not match the shape of the patient, the seal-forming portion can fold or buckle during use, causing leakage.

[0039] Other types of seal-forming structures may include friction-fit elements that are inserted into the nostrils, for example, but some patients find these seal-forming parts uncomfortable.

[0040] Another form of seal-forming structure may use adhesives to achieve a seal, as some patients find it inconvenient to constantly apply and remove adhesives from their face.

[0041] A range of patient interface seal forming structures are disclosed in the following patent applications (assigned to ResMed Limited: WO1998 / 004,310; WO2006 / 074,513; WO2010 / 135,785).

[0042] One form of nasal pillow is found in the Adam line manufactured by Puritan Bennett. Another nasal pillow or nasal puff is the subject of U.S. Pat. No. 4,782,832 (Trimble et al.), assigned to Puritan-Bennett Corporation.

[0043] ResMed Limited manufactures the following products that use nasal pillows: SWIFT® Nasal Pillows Mask, SWIFT® II Nasal Pillows Mask, SWIFT® LT Nasal Pillows Mask, SWIFT® FX Nasal Pillows Mask, and MIRAGELIBERTY® Full Face Mask. Embodiments of nasal pillow masks are described in the following patent applications assigned to ResMed Limited: International Patent Application WO 2004 / 073,778 (which describes, among other things, aspects of ResMed Limited's SWIFT® Nasal Pillows); U.S. Patent Application No. 2009 / 0044808 (which describes, among other things, aspects of ResMed Limited's SWIFT® LT Nasal Pillows); International Patent Applications WO 2005 / 063,328 and WO 2006 / 130,903 (which describe, among other things, aspects of ResMed Limited's MIRAGE LIBERTY® Full Face Mask); and International Patent Application WO 2009 / 052,560 (which describes, among other things, aspects of ResMed Limited's SWIFT® FX Nasal Pillows).

[0044] 2.2.3.1.2 Positioning and stabilization The seal-forming structures of patient interfaces used in positive air pressure therapy are subjected to corresponding forces of air pressure that disrupt the seal, and therefore a variety of techniques are used to position the seal-forming structures and maintain a seal against the appropriate portion of the face.

[0045] One technique involves the use of adhesives, see, for example, U.S. Patent Application Publication No. US2010 / 0000534, but adhesives can be uncomfortable.

[0046] Another technique involves the use of one or more straps and / or stabilizing harnesses, many of which suffer from one or more of the following problems: poor fit, bulky, uncomfortable, and cumbersome.

[0047] 2.2.3.2 Respiratory Pressure Therapy (RPT) Devices Respiratory pressure therapy (RPT) devices can be used to deliver one or more of the above-mentioned therapies, for example, by generating a flow of air delivery to the airway entrance. This flow of air can be pressurized. Examples of RPT devices include CPAP devices and mechanical ventilators.

[0048] Air pressure generators are known for a wide range of applications (e.g., industrial-scale ventilation systems). However, air pressure generators for medical applications have specific requirements that cannot be met by more common air pressure generators (e.g., the reliability, size, and weight requirements of medical equipment). In addition, even devices designed for medical treatment may suffer from deficiencies related to one or more of the following: comfort, noise, ease of use, effectiveness, size, weight, manufacturability, cost, and reliability.

[0049] One example of a special requirement for a particular RPT device is acoustic noise.

[0050] [Table 1]

[0051] One known RPT device used to treat sleep-disordered breathing is the S9 Sleep Therapy System (manufactured by ResMed Limited). Another example of an RPT device is a ventilator. Ventilators (e.g., the ResMed Stellar® series of adult and pediatric ventilators) can provide invasive and non-invasive independent respiratory support for patients for a range of conditions, including, but not limited to, NMD, OHS, and COPD.

[0052] The ResMed Elise'e® 150 ventilator and ResMed VSIII® ventilators can provide invasive and non-invasive dependent respiratory support suitable for adult or pediatric patients for the treatment of multiple conditions. These ventilators offer volumetric and pressure ventilation modes using single or dual limb circuits. RPT devices typically include a pressure generator (e.g., an electric blower or compressed gas reservoir) and are configured to deliver airflow to the patient's airway. In some cases, the airflow can be delivered to the patient's airway at positive pressure. The outlet of the RPT device is connected via an air circuit to a patient interface, as described above.

[0053] A device designer may be presented with a myriad of choices. Often, conflicting design criteria may make certain design choices unconventional or unavoidable. Furthermore, the comfort and effectiveness of a particular implementation may be significantly affected by minor changes in one or more parameters.

[0054] 2.2.3.3 Humidifier Delivery of airflow without humidification can lead to dryness of the airway. When a humidifier is used with an RPT device and patient interface, humidified gas is produced, minimizing drying of the nasal mucosa and increasing patient airway comfort. Additionally, in cooler climates, the application of warm air to the facial area surrounding the patient interface generally provides more comfort than cool air.

[0055] A range of artificial humidification devices and systems are known, but do not meet the special requirements of medical humidifiers.

[0056] Medical humidifiers are typically used when a patient is sleeping or resting (e.g., in a hospital) to increase the humidity and / or temperature of an air stream relative to the ambient air when needed. Bedside medical humidifiers may be compact. Medical humidifiers may be configured to only humidify and / or heat the air stream delivered to the patient, not the patient's surroundings. For example, while room-based systems (e.g., saunas, air conditioners, or evaporative coolers) may also humidify the air breathed into the patient's body, these systems also humidify and / or heat the entire room, which may be uncomfortable for occupants. Additionally, medical humidifiers may have more stringent safety constraints than industrial humidifiers.

[0057] Although many medical humidifiers are known, such medical humidifiers may suffer from one or more deficiencies, such that some provide inadequate humidification or are difficult or inconvenient for the patient to use.

[0058] 2.2.3.4 Data Management For clinical reasons, data may be obtained to determine whether a patient prescribed respiratory therapy is "compliant" (e.g., whether the patient adheres to certain "compliance rules" for their RPT device). An example of a compliance rule for CPAP therapy may require a patient to use the RPT device for at least four hours per night for at least 21 days out of 30 consecutive days to be considered compliant. To determine patient compliance, a provider of the RPT device (e.g., a healthcare provider) may manually obtain data describing the patient's treatment with the RPT device, calculate usage rates over a given period, and compare this to the compliance rules. Once the healthcare provider determines that the patient has used their RPT device in accordance with the compliance rules, the healthcare provider may notify a third party that the patient is compliant.

[0059] There may be other aspects of patient care that benefit from communication of treatment data to third parties or external systems.

[0060] Existing processes for communicating and managing such data can be costly, time consuming, and / or error prone.

[0061] 2.2.3.5 Mandibular repositioning A mandibular repositioning device (MRD) or mandibular advancement device (MAD) is one treatment option for sleep apnea and snoring. It is an adjustable oral appliance available from dentists or other suppliers that holds the mandible (lower jaw) in an anterior position during sleep. MRDs are removable devices that are inserted into the mouth before a patient goes to sleep and removed afterward. As such, MRDs are not designed for full-time wear. MRDs can be custom-made or manufactured in standard forms and include bite impression sections designed to fit the patient's teeth. This mechanical protrusion from the mandible expands the space behind the tongue and applies tension on the pharyngeal walls, reducing airway collapse and palatal vibration.

[0062] In certain embodiments, the mandibular advancement device may include an upper splint intended to engage or mate with teeth on the upper jaw or maxilla, and a lower splint intended to engage or mate with teeth on the upper jaw or mandible. The upper and lower splints are laterally connected to each other via a pair of connecting rods that are fixed symmetrically on the upper and lower splints.

[0063] In such a design, the length of the connecting rod is selected so that the mandible is held in a forward position when the MRD is placed in the patient's mouth. The length of the connecting rod can be adjusted to change the level of mandibular protrusion. The dentist can determine the level of protrusion required for the mandible, and the length of the connecting rod is then determined.

[0064] Some MRDs are configured to push the mandible forward relative to the maxilla, while others, such as the ResMed Narval CC® MRD, are designed to hold the mandible in a forward position. The devices also reduce or minimize dental and temporomandibular joint (TMJ) side effects. As such, the devices are configured to minimize or prevent any movement of one or more teeth.

[0065] 2.2.3.6 Ventilation technology Some forms of treatment systems may include a vent to push exhaled carbon dioxide out, which may allow flow from an interior space of the patient interface (e.g., a plenum chamber) to an exterior of the patient interface (e.g., ambient).

[0066] The vents may include orifices through which gas can flow when the mask is in use. Many such vents are noisy. Others may become blocked during use, resulting in insufficient pumping. Some vents may disrupt sleep for the patient 1000 and bed companion 1100, for example, due to noise or concentrated airflow.

[0067] ResMed Limited has developed several improved mask ventilation technologies, see International Patent Application Publication No. WO 1998 / 034,665; International Patent Application Publication No. WO 2000 / 078,381; U.S. Patent No. 6,581,594; U.S. Patent Application Publication No. US 2009 / 0050156; and U.S. Patent Application Publication No. 2009 / 0044808.

[0068] [Table 2]

[0069] (*Measured using only one sample at 10cmH2O in CPAP mode using the test method specified in ISO3744)

[0070] [Table 3]

[0071] 2.2.4 Diagnostic and Monitoring Systems Polysomnography (PSG) is a conventional system for diagnosing and monitoring cardiopulmonary diseases and typically requires specialized clinical staff for system application. PSG typically involves placing 15–20 contact sensors on the body to record various body signals (e.g., electroencephalography (EEG), electrocardiography (ECG), electrooculography (EOG), and electromyography (EMG)). PSG for sleep-disordered breathing requires patients to be observed for two nights in a specialized hospital: the first night for pure diagnosis and the second night for clinician-assisted titration of treatment parameters. Therefore, PSG is expensive and inconvenient. PSG is particularly unsuitable for home sleep testing.

[0072] A clinical expert may adequately diagnose or monitor a patient based on visual observation of the PSG signal. However, there are situations where a clinical expert is not available or cannot be paid for. Different clinical experts may have different opinions about a patient's condition. Furthermore, some clinical experts may apply different criteria at different times. Summary of the Invention [Means for solving the problem]

[0073] 3. Brief description of the technology The present technology relates to the provision of medical devices for use in the diagnosis, amelioration, treatment or prevention of respiratory disorders, which medical devices have one or more of improved comfort, cost, effectiveness, ease of use and manufacturability.

[0074] A first aspect of the present technology relates to devices used in the diagnosis, amelioration, treatment or prevention of respiratory disorders.

[0075] Another aspect of the present technology relates to methods for use in the diagnosis, amelioration, treatment or prevention of respiratory disorders.

[0076] An aspect of certain forms of the present technology is to provide methods and / or devices that improve patient compliance with respiratory therapy.

[0077] Aspects of the present technology relate to a seal-forming structure for a patient interface configured to form a seal with a patient's nares, the seal-forming structure including a support structure that forms a continuous loop with an inner surface of the seal-forming structure, the loop structure supporting an upper portion of a patient-contacting surface of the seal-forming structure, the upper portion of the patient-contacting surface having a single layer that is not supported by an undercushion.

[0078] Aspects of the present technology relate to a patient interface comprising: a plenum chamber pressurizable to a therapeutic pressure of at least 6 cmH2O above ambient air pressure, said plenum chamber including a plenum chamber inlet port sized and configured to receive airflow at the therapeutic pressure for breathing by the patient; a seal-forming structure constructed and arranged to form a seal with the plenum chamber and an area of the patient's face surrounding an entrance to the patient's airways, the seal-forming structure constructed and arranged to maintain the therapeutic pressure in the plenum chamber throughout the patient's respiratory cycle in use; and a positioning and stabilizing structure providing a force to hold the seal-forming structure in a therapeutically effective position on the patient's head, the positioning and stabilizing structure including a tie, the tie constructed and arranged to be positioned at least partially over an area of the patient's head above the supra-ear point in use. and a venting structure for transferring a continuous flow of gases exhaled by the patient from the interior of the plenum chamber to the atmosphere, the venting structure being sized and shaped to maintain a therapeutic pressure in the plenum chamber in use; the patient interface is configured to allow the patient to breathe from the atmosphere through their oral cavity in the absence of pressurized air flow through the plenum chamber inlet port, or alternatively, the patient interface is configured to leave the patient's oral cavity exposed; the seal-forming structure further includes a patient-contacting surface configured to engage the patient's facial skin to form a seal, and a rear opening formed in the patient-contacting surface, the rear opening being configured to provide the air flow at the therapeutic pressure to the patient's nares; and the seal-forming structure includes a support structure extending from a first location on the patient-contacting surface to a second location on an inner surface of the seal-forming structure, the support structure and the inner surface forming a continuous loop.

[0079] In examples, (a) the seal-forming structure may include a front opening formed in the non-patient-contacting surface and a front tie covering the front opening, and a first end of the support structure may be connected to the front tie, (b) the seal-forming structure may include a rim bounding a posterior opening in the patient-contacting surface, and a second end of the support structure may be connected to the patient-contacting surface at an upper region of the rim, (c) the seal-forming structure may include an undercushion supporting the patient-contacting surface, (d) a lower portion of the seal-forming structure may include an undercushion and an upper portion of the seal-forming structure may not include an undercushion, (e) the support structure may have a length in the undeformed state that is longer than the linear distance from the first position to the second position, (f) the support structure may be configured to be positioned in contact with or adjacent to the bridge of the patient's nose in use, and (g) the support structure may be configured to be positioned in the undeformed state (h) the support structure may have a different thickness than the patient-contacting surface, (i) the support structure may be thicker than the patient-contacting surface, (j) the support structure may not extend entirely through the rear opening, (k) the seal-forming structure may at least partially form a gas chamber, and the support structure may extend into the gas chamber in the undeformed state, (l) the support structure may have a variable thickness in the longitudinal direction, (n) the support structure may have an increased thickness adjacent the first position and / or the second position, (n) a portion of the support structure may be curved away from the patient's nose along the longitudinal axis of the support structure in the undeformed state, and / or (o) the undercushion may be configured to support the patient-contacting surface only against the patient's upper lip.

[0080] Aspects of the present technology relate to a seal-forming structure for a patient interface, the seal-forming structure constructed and arranged to form a seal with an area of a patient's face surrounding an entrance to the patient's airway, the seal-forming structure constructed and arranged to maintain a therapeutic pressure in a plenum chamber of at least 6 cmH2O above ambient air pressure throughout the patient's respiratory cycle in use. The seal-forming structure includes a patient-contacting surface configured to engage the patient's facial skin to form a seal, a rear opening formed in the patient-contacting surface, the rear opening configured to provide airflow at the therapeutic pressure to the patient's nares, and a support structure extending from a first location on the patient-contacting surface to a second location on an inner surface of the seal-forming structure, the support structure and the inner surface forming a continuous loop, the patient interface configured to allow the patient to breathe from atmosphere through their oral cavity in the absence of pressurized airflow through the plenum chamber inlet port, or alternatively, the patient interface configured to leave the patient's oral cavity exposed.

[0081] In examples, (a) the seal-forming structure may include a front opening formed in the non-patient-contacting surface and a front tie covering the front opening, and a first end of the support structure may be connected to the front tie, (b) the seal-forming structure may include a rim bounding a posterior opening in the patient-contacting surface, and a second end of the support structure may be connected to the patient-contacting surface at an upper region of the rim, (c) the seal-forming structure may include an undercushion supporting the patient-contacting surface, (d) a lower portion of the seal-forming structure may include an undercushion and an upper portion of the seal-forming structure may not include an undercushion, (e) the support structure may have a length in the undeformed state that is longer than the linear distance from the first position to the second position, (f) the support structure may be configured to be positioned in contact with or adjacent to the bridge of the patient's nose in use, and (g) the support structure may be configured to be positioned in the undeformed state (h) the support structure may have a different thickness than the patient-contacting surface, (i) the support structure may be thicker than the patient-contacting surface, (j) the support structure may not extend entirely through the rear opening, (k) the seal-forming structure may at least partially form a gas chamber, and the support structure may extend into the gas chamber in the undeformed state, (l) the support structure may have a variable thickness in the longitudinal direction, (n) the support structure may have an increased thickness adjacent the first position and / or the second position, (n) a portion of the support structure may be curved away from the patient's nose along the longitudinal axis of the support structure in the undeformed state, and / or (o) the undercushion may be configured to support the patient-contacting surface only against the patient's upper lip.

[0082] Aspects of the present technology relate to a patient interface including: a plenum chamber pressurizable to a therapeutic pressure of at least 6 cmH2O above ambient air pressure, said plenum chamber including a plenum chamber inlet port sized and configured to receive a flow of air at the therapeutic pressure for breathing by the patient; a seal-forming structure constructed and arranged to form a seal with an area of the patient's face surrounding an entrance to the patient's airways, the seal-forming structure constructed and arranged to maintain the therapeutic pressure in the plenum chamber throughout the patient's respiratory cycle in use; and a positioning and stabilizing structure providing a force to hold the seal-forming structure in a therapeutically effective position on the patient's head, the positioning and stabilizing structure a positioning and stabilizing structure including a tie constructed and arranged such that, in use, at least a portion of the tie is positioned on a region of the patient's head above the ear base of the patient's head; a decoupling structure; and a venting structure that transfers a continuous flow of gases exhaled by the patient from the interior of the plenum chamber to the atmosphere, the venting structure being sized and shaped such that, in use, a therapeutic pressure can be maintained within the plenum chamber, the patient interface being configured to allow the patient to breathe from the atmosphere through their oral cavity in the absence of pressurized air flow through the plenum chamber inlet port, or alternatively, the patient interface being configured to leave the patient's oral cavity exposed, the venting structure further including an opening through the decoupling structure and an opening through the plenum chamber.

[0083] Another aspect of one form of the present technology is a patient interface that is molded or otherwise constructed with a peripheral shape that is complimentary to the shape of the intended wearer.

[0084] One aspect of the present technology is a method for manufacturing a device.

[0085] One aspect of certain forms of the present technology is a medical device that is easy to use, for example, by individuals without medical training, individuals with limited dexterity or acumen, or individuals with limited experience using such medical devices.

[0086] An aspect of one form of the present technology is a patient interface that can be cleaned at the patient's home, for example with soapy water, without the need for special cleaning equipment.An aspect of one form of the present technology is a patient interface that can be cleaned at the patient's home, for example with soapy water, without the need for special cleaning equipment.

[0087] Of course, some of the above aspects may form sub-aspects of the present technology, and various sub-aspects and / or aspects may be combined in various ways to form further aspects or sub-aspects of the present technology.

[0088] Other features of the present technology will become apparent in light of the information contained in the following detailed description, abstract, drawings, and claims. [Brief explanation of the drawings]

[0089] 4 Brief description of the drawings The present technology is illustrated by way of example and not limitation in the accompanying drawings, in which like reference numerals include like elements:

[0090] 4.1 Treatment System [Figure 1A] 1A shows a system including a patient 1000 wearing a patient interface 3000, which takes the form of nasal pillows and receives air at positive pressure supplied by an RPT device 4000. The air from the RPT device 4000 is humidified by a humidifier 5000 and travels along an air circuit 4170 to the patient 1000. A bed companion 1100 is also shown. The patient is sleeping in a supine sleeping position. [Figure 1B]1B shows a system including a patient 1000 wearing a patient interface 3000. The system takes the form of a nasal mask and receives air at positive pressure supplied by an RPT device 4000. The air from the RPT device is humidified by a humidifier 5000 and travels along an air circuit 4170 to the patient 1000. [Figure 1C] 1C shows a system including a patient 1000 wearing a patient interface 3000. The patient interface 3000 takes the form of a full face mask and receives a supply of air at positive pressure from an RPT device 4000. The air from the RPT device is humidified by a humidifier 5000 and travels along an air circuit 4170 to the patient 1000. The patient is sleeping in a lateral sleeping position.

[0091] 4.2 Respiratory System and Facial Anatomy [Figure 2A] Figure 2A shows an overview of the human respiratory system, including the nasal and oral cavities, larynx, vocal folds, esophagus, trachea, bronchi, lungs, alveolar sacs, heart, and diaphragm. [Figure 2B] FIG. 2B is a diagram of the human upper respiratory tract, including the nasal cavity, nasal bones, lateral nasal cartilages, greater alar cartilages, nostrils, upper lip, lower lip, larynx, hard palate, soft palate, oropharynx, tongue, epiglottis, vocal folds, esophagus, and trachea. [Figure 2C] Figure 2C is a front view of the face including several features of the surface anatomy, including the upper lip, vermilion, vermilion, lower lip, mouth width, medial canthus, alae of the nose, nasolabial folds, and corners of the mouth. The directions of superior, inferior, radially inward, and radially outward are also noted. [Figure 2D] Figure 2D is a side view of the head including several features of the surface anatomy, including the glabella, serrion, nasal tip, subnasal point, upper lip, lower lip, supramenton, nasal ridge, ala crest, supra- and sub-auricular points. The directions of superior and inferior, anterior and posterior are also indicated. [Figure 2E] Figure 2E is a further lateral view of the head. The approximate locations of the Frankfort horizontal and nasolabial angle are noted. The coronal view is also noted. [Figure 2F]FIG. 2F is a bottom view of the nose including several features including the nasolabial fold, lower lip, vermilion, nostrils, subnasal point, columella, nasal tip, major axis of the nostrils and midsagittal plane. [Figure 2G] FIG. 2G is a side view of the surface features of the nose. [Figure 2H] Figure 2H shows the subcutaneous structures of the nose, including the lateral nasal cartilages, nasal septum cartilage, greater alar cartilage, lesser alar cartilage, nasal sesamoid cartilage, nasal bones, epidermis, adipose tissue, frontal process of the maxilla, and fibro-adipose tissue. [Figure 2I] Figure 2I shows a mid-nasal incision approximately a few millimeters from the midsagittal plane, specifically showing the nasal septum cartilage and the medial crus of the greater alar cartilage. [Figure 2J] Figure 2J is a bony frontal view of the skull, including the frontal, nasal, and zygomatic bones. The nasal turbinates are shown along with the maxilla and mandible. [Figure 2K] Figure 2K is a side view of the skull, showing the outline of the head surface and some muscles. The following bones are shown: frontal, sphenoid, nasal, zygomatic, maxilla, mandible, parietal, temporal, and occipital. The mental protuberance is shown. The following muscles are shown: digastric, masseter, sternocleidomastoid, and trapezius. [Figure 2L] Figure 2L shows the anterolateral aspect of the nose.

[0092] 4.3 Patient Interface [Figure 3A] FIG. 3A shows a patient interface in the form of a nasal mask in accordance with one form of the present technology. [Figure 3B] Figure 3B is a schematic cross-sectional view of the structure cut at a point, showing the outward normal at this point, and the curvature at this point has a positive sign and a relatively large magnitude compared to the magnitude of the curvature shown in 3C. [Figure 3C] Figure 3C is a schematic cross-sectional view of the structure cut at a point, showing the outward normal at this point. The curvature at this point has a positive sign and a relatively small magnitude compared to the magnitude of the curvature shown in Figure 3B. [Figure 3D]Figure 3D is a schematic cross-sectional view of the structure cut at a point, where the outward normal is shown and the curvature at this point is zero. [Figure 3E] Figure 3E is a schematic cross-sectional view of the structure taken at a point, showing the outward normal at this point. The curvature at this point has a negative sign and a relatively small magnitude compared to the magnitude of the curvature shown in Figure 3F. [Figure 3F] Figure 3F is a schematic cross-sectional view of the structure taken at a point, showing the outward normal at this point. The curvature at this point has a negative sign and a relatively large magnitude compared to the magnitude of the curvature shown in Figure 3E. [Figure 3G] 3G shows a mask cushion including two pillows, the outer surface of the cushion is shown, the edge of the surface is shown, and the dome and saddle regions are shown. [Figure 3H] 3H shows a cushion for a mask. The outer surface of the cushion is shown. The edge of the surface is shown. The path on the surface between points A and B is shown. The linear distance between A and B is shown. Two saddle regions and a dome region are shown. [Figure 3I] Figure 3I shows the surface of a structure with a one-dimensional hole drilled into it. The planar curves shown form the boundary of the one-dimensional hole. [Figure 3J] Figure 3J is a cross-sectional view through the structure of Figure 31. The surfaces shown bound a two-dimensional hole in the structure of Figure 31. [Figure 3K] Figure 3K is a perspective view of the structure of Figure 3I including two-dimensional and one-dimensional holes, and also illustrates the surfaces bounding the two-dimensional holes in the structure of Figure 3I. [Figure 3L] FIG. 3L shows a mask with an inflatable bladder as a cushion. [Figure 3M] Figure 3M is a cross-sectional view of the mask of Figure 3L showing the inner surface of the bladder, which bounds the two-dimensional hole in the mask. [Figure 3N] Figure 3N shows a further cross section through the mask of Figure 3L, the interior surface also being shown. [Figure 3O] Figure 3O illustrates the left-hand rule. [Figure 3P] Figure 3P illustrates the right-hand rule. [Figure 3Q] FIG. 3Q shows the left ear including the left ear helix. [Figure 3R] FIG. 3R shows the right ear including the right ear helix. [Figure 3S] Figure 3S shows a right-handed spiral. [Figure 3T] FIG. 3T is a diagram of a mask including the signature of the twist of the space curve defined by the edges of the sealing membrane in different regions of the mask. [Figure 3U] FIG. 3U is a diagram of the plenum chamber (cushion assembly) 3200 showing the midsagittal plane and the central contact plane. [Figure 3V] Figure 3V is a posterior view of the plenum chamber of Figure 3U. Directions in the figure are perpendicular to the central contact plane. In Figure 3V, the midsagittal plane bisects the plenum chamber into a left-hand side and a right-hand side. [Figure 3W] Figure 3W is a cross-sectional view through the plenum chamber of Figure 3V, the cross-section being taken in the midsagittal plane shown in Figure 3V. The "central contact" plane is shown. The central contact plane is perpendicular to the midsagittal plane. The orientation of the central contact plane corresponds to the orientation of the tendon 3210. The tendon 3210 rests on the midsagittal plane and contacts the plenum chamber cushion only at two points on the midsagittal plane (i.e., superior point 3220 and inferior point 3230). Depending on the geometry of the cushion in this region, the central contact plane may contact both the superior and inferior points. [Figure 3X] Figure 3X shows the plenum chamber 3200 of Figure 3U in a use position on the face. The midsagittal plane of the plenum chamber 3200 generally coincides with the midsagittal plane of the face when the plenum chamber is in the use position. The central contact plane generally corresponds to the "face plane" when the plenum chamber is in the use position. In Figure 3X, the plenum chamber 3200 is that of a nasal mask, with the upper point 3220 resting approximately on the selion and the lower point 3230 resting on the upper lip.

[0093] 4.4 RPT Device [Figure 4A] 4 shows an RPT device 4000 in accordance with one form of the present technology. [Figure 4B] 1 is a schematic diagram of an air circuit of an RPT device 4000 in accordance with one form of the present technology. Upstream and downstream directions are indicated relative to the blower and patient interface. Regardless of the actual flow direction at any particular moment, the blower is defined as being upstream of the patient interface, and the patient interface is defined as being downstream of the blower. Items located in the pneumatic path between the blower and the patient interface are downstream of the blower and upstream of the patient interface.

[0094] 4.5 Humidifier [Figure 5A] FIG. 5A is an isometric view of a humidifier in accordance with one form of the present technology. [Figure 5B] FIG. 5B is an isometric view of a humidifier in accordance with one form of the present technology, showing the humidifier reservoir 5110 removed from the humidifier reservoir dock 5130.

[0095] 4.6 Respiratory waveform [Figure 6] FIG. 6 shows a model of a typical human respiratory waveform during sleep.

[0096] 4.7 Patient interface using this technology [Figure 7A] FIG. 7A is a front perspective view of a seal-forming structure of a patient interface according to an embodiment of the present technology. [Figure 7B] FIG. 7B is a front view of a seal-forming structure of a patient interface according to an embodiment of the present technology. [Figure 7C] FIG. 7C is a side view of a seal-forming structure of a patient interface according to an embodiment of the present technology. [Figure 7D] FIG. 7D is a posterior view of a seal-forming structure of a patient interface according to an embodiment of the present technology. [Figure 7E] FIG. 7E shows an inferior view of a seal-forming structure of a patient interface according to an embodiment of the present technology. [Figure 7F] FIG. 7F shows a top view of a seal-forming structure of a patient interface according to an embodiment of the present technology. [Figure 7G] FIG. 7G is a cross-sectional view of the seal-forming structure of the patient interface taken at line 7J-7J of FIG. 7B in accordance with an embodiment of the present technology. [Figure 7H] 7H is a cross-sectional view of the seal-forming structure of the patient interface taken at line 7H-7H of FIG. 7B in accordance with an embodiment of the present technology. [Figure 7I] FIG. 7I is a cross-sectional view of a seal-forming structure of a patient interface taken at line 7I-7I of FIG. 7B in accordance with an embodiment of the present technology. [Figure 7J] 7J is a cross-sectional view of a seal-forming structure of a patient interface taken at line 7J-7J of FIG. 7B in accordance with an embodiment of the present technology. [Figure 7K] FIG. 7K is a cross-sectional view of a seal-forming structure of a patient interface taken at line 7K-7K of FIG. 7C in accordance with an embodiment of the present technology. [Figure 7L] FIG. 7L is a cross-sectional view of the seal-forming structure of the patient interface taken at line 7L-7L of FIG. 7C in accordance with an embodiment of the present technology. [Figure 7M] FIG. 7M is a cross-sectional view of a seal-forming structure of a patient interface taken at line 7M-7M of FIG. 7C in accordance with an embodiment of the present technology. [Figure 8A] FIG. 8A is a rear perspective view of a decoupling structure of a patient interface according to an embodiment of the present technology. [Figure 8B] FIG. 8B is a front perspective view of a decoupling structure of a patient interface according to an embodiment of the present technology. [Figure 9A] FIG. 9A is a rear perspective view of a decoupling structure of a patient interface according to an embodiment of the present technology. [Figure 9B]FIG. 9B is a front perspective view of a decoupling structure of a patient interface according to an embodiment of the present technology. [Figure 10] FIG. 10A is a top perspective view of a patient interface according to an embodiment of the present technology. [Figure 11] FIG. 11 is a front perspective view of a patient interface according to an embodiment of the present technology. DETAILED DESCRIPTION OF THE INVENTION

[0097] 5 Detailed Description of the Embodiments of the Present Technology Before describing the present technology in further detail, it is to be understood that the present technology is not limited to the specific embodiments described herein, which may vary. It is also to be understood that the terminology used in the present disclosure is for the purpose of describing the specific embodiments described herein, and is not intended to be limiting.

[0098] The following description is provided in connection with various embodiments that may share one or more common characteristics and / or features. It should be understood that one or more features of any one embodiment may be combined with one or more features of another embodiment or other embodiments. In addition, any single feature or combination of features in any of these embodiments may constitute an additional embodiment.

[0099] 5.1 Treatment In one form, the present technology includes a method of treating a respiratory disorder, the method including applying positive pressure to the entrance of the airways of a patient 1000.

[0100] In certain embodiments of the present technology, a supply of air at positive pressure is provided to the patient's nasal passages via one or both nostrils.

[0101] In certain embodiments of the present technology, mouth breathing is restricted, limited or prevented.

[0102] 5.2 Treatment System In one form, the present technology includes an apparatus or device for the treatment of disordered breathing. The apparatus or device may include an RPT device 4000 that supplies pressurized air to the patient 1000 via an air circuit 4170 to a patient interface 3000.

[0103] 5.3 Patient Interface A non-invasive patient interface 3000 in accordance with one aspect of the present technology includes the following functional features: a seal-forming structure 3100, a plenum chamber 3200, a positioning and stabilizing structure 3300, a vent 3400, a form of connection port 3600 for connection to an air circuit 4170, and a forehead support 3700. In some forms, the functional features may be provided by one or more physical components. In some forms, a single physical component may provide one or more functional features. In use, the seal-forming structure 3100 is positioned to surround the entrance to the patient's airways to facilitate the delivery of air at positive pressure to the airways.

[0104] If the patient interface cannot comfortably deliver a minimum level of positive pressure to the airway, the patient interface may be unsuitable for respiratory pressure therapy.

[0105] A patient interface 3000 in accordance with one form of the present technology is constructed and arranged to provide an air supply at a positive pressure of at least 6 cmH2O relative to ambient.

[0106] A patient interface 3000 in accordance with one form of the present technology is constructed and arranged to provide an air supply at a positive pressure of at least 10 cmH2O relative to ambient.

[0107] A patient interface 3000 in accordance with one form of the present technology is constructed and arranged to provide an air supply at a positive pressure of at least 20 cmH2O relative to ambient.

[0108] 5.3.1 Seal formation structure In one form of the present technology, the seal-forming structure 3100 provides a target seal-forming area and may further provide a cushioning function. The target seal-forming area is the area where a seal may occur in the seal-forming structure 3100. The area where a seal actually occurs (i.e., the actual sealing surface) may vary from patient to patient in a given treatment session and from day to day, depending on a range of factors (e.g., placement of the patient interface on the face, tension in the positioning and stabilizing structure, and the shape of the patient's face).

[0109] In one form, the target seal-forming area is located on an exterior surface of the seal-forming structure 3100 .

[0110] In certain forms of the present technology, the seal-forming structure 3100 is constructed from a biocompatible material (eg, silicone rubber).

[0111] A seal-forming structure 3100 according to the present technology may be constructed from a soft, flexible and resilient material (eg, silicone).

[0112] In certain forms of the present technology, a system is provided that includes more than one seal-forming structure 3100. Each seal-forming structure 3100 is configured to accommodate a different size and / or shape range. For example, the system may include one form of seal-forming structure 3100 that is suitable for large head sizes but not small head sizes, and another that is suitable for small head sizes but not large head sizes.

[0113] 5.3.1.1 Sealing mechanism In one form, the seal-forming structure includes a sealing flange that employs a pressure-assisted sealing mechanism. In use, the sealing flange can readily respond to positive system pressure within the plenum chamber 3200 by acting on its underside to form a tight sealing engagement with the surface. The pressure-assisted mechanism can work in conjunction with elastic tension in the positioning and stabilizing structure.

[0114] In one form, the seal-forming structure 3100 includes a sealing flange and a support flange. The sealing flange includes a relatively thin member having a thickness of less than about 1 mm (e.g., about 0.25 mm to about 0.45 mm) that extends around the peripheral length of the plenum chamber 3200. The support flange may be relatively thicker than the sealing flange. The support flange is disposed between the sealing flange and the peripheral edge of the plenum chamber 3200 and extends around at least a portion of the peripheral length. The support flange is or includes a spring-like element that functions to support the sealing flange against buckling during use.

[0115] In one form, the seal-forming structure may include a compression seal or gasket seal that is constructed and arranged to be in compression in use due to, for example, elastic tension in the positioning and stabilizing structure.

[0116] In one form, the seal-forming structure includes a tensioning portion that, in use, is held taut by, for example, an adjacent region of the sealing flange.

[0117] In one form, the seal-forming structure includes an area having a sticky or adhesive surface.

[0118] In certain forms of the present technology, the seal-forming structure may include one or more of a pressure-assisted sealing flange, a compression seal, a gasket seal, a tension section, and a section having a sticky or adhesive surface.

[0119] 5.3.1.2 Nasal bridge or nasal ridge area In one form, the non-invasive patient interface 3000 includes a seal-forming structure that, in use, forms a seal on the nasal bridge or nasal ridge region of the patient's face.

[0120] In one form, the seal-forming structure includes a saddle-shaped region constructed to form a seal over the nasal bridge or nasal ridge region of the patient's face in use.

[0121] 5.3.1.3 Upper lip area In one form, the non-invasive patient interface 3000 includes a seal-forming structure that, in use, forms a seal over the upper lip region (ie, upper lip) of the patient's face.

[0122] In one form, the seal-forming structure includes a saddle-shaped region constructed to form a seal over the upper lip region of the patient's face in use.

[0123] 5.3.1.4 Jaw area In one form, the non-invasive patient interface 3000 includes a seal-forming structure that, in use, forms a seal over the chin region of the patient's face.

[0124] In one form, the seal-forming structure includes a saddle-shaped region constructed to form a seal over the chin region of the patient's face in use.

[0125] 5.3.1.5 Frontal Area In one form, the seal-forming structure forms a seal on the forehead region of the patient's face when in use, and in such a form, the plenum chamber may cover the eyes when in use.

[0126] 5.3.1.6 Nasal pillow In one form, the seal-forming structure of the non-invasive patient interface 3000 includes a pair of nasal puffs or nasal pillows, each constructed and arranged to form a seal with a respective nostril of the patient's nose.

[0127] Nasal pillows according to one aspect of the present technology include a truncated cone. At least a portion of the truncated cone forms a seal over the underside of the patient's nose, the stem, and a flexible region on the underside of the truncated cone, connecting the truncated cone to the stem. Additionally, the structure to which the nasal pillows of the present technology are connected includes a flexible region adjacent to the base of the stem. The flexible region can function to facilitate a universal joint structure. The universal joint structure accommodates both the displacement and angle of the truncated cone and the relative movement of the structure to which the nasal pillows are connected. For example, the truncated cone can be displaced axially toward the structure to which the stem is connected.

[0128] 5.3.1.7 Seal formation structure using support structure 7A-7M show a seal-forming structure 3100 in accordance with an example of the present technology. The seal-forming structure 3100 may be characterized as a nasal cradle cushion. The seal-forming structure 3100 may be configured to seal against a patient's face around the patient's nostrils to deliver pressurized breathable air to the patient's nasal airways (without covering the patient's oral cavity).

[0129] The lower portion of the seal-forming structure 3100 may engage with the patient's upper lip to form a seal, and the seal-forming structure 3100 may not extend beyond the upper lip to the patient's vermilion. In one example, the upper portion of the seal-forming structure 3100 may be structured to engage with the patient's nose below the patient's nasal bone to form a seal. In another example, the upper portion of the seal-forming structure 3100 may be structured to engage with the patient's nose below the patient's nasal tip to form a seal. The lateral portions of the seal-forming structure 3100 may be structured to engage with the patient's face between the patient's ala and the patient's cheek to form a seal. The lateral portions of the seal-forming structure 3100 may be structured to engage with the patient's face beyond the ala crest and form a seal.

[0130] The seal-forming structure 3100 according to the present technology may include attributes of the nasal cradle cushions disclosed in International Application Publication Nos. WO2014 / 110626 (filed January 16, 2014) and WO2015 / 070289 (filed November 14, 2014), each of which is incorporated by reference in its entirety herein.

[0131] 7A-7M includes a connection region 3102 on its forward side. The connection region 3102 is structured to connect the seal-forming structure 3100 to the plenum chamber 3200. The connection region 3102 provides an interface that engages with the plenum chamber 3200. The connection region 3102 may connect to the plenum chamber 3200 via a mechanical connection (e.g., a friction fit, a snap fit, or a mechanical interlock of corresponding overhanging portions). The connection region 3102 may provide a removable connection to the plenum chamber 3200. This removable connection allows the seal-forming structure 3100 to be removed for cleaning or replacement.

[0132] The connection region 3102 in this example surrounds a front opening 3104 or hole. The front opening 3104 may be in fluid communication with the plenum chamber 3200 to receive a flow of pressurized breathable gas, and exhaled gases from the patient may travel through the front opening 3104 to the plenum chamber 3200 and be exhausted through the vent 3400. The front opening 3104 in this example is also divided by a front tie 3108 that vertically encompasses the front opening 3104 between a lower portion of the connection region 3102 and an upper portion of the connection region 3102.

[0133] The seal-forming structure 3100 of this example also includes a non-patient-contacting surface 3116 that surrounds the connection region 3102. The non-patient-contacting surface 3116 faces away from the patient's face in use and does not contact the patient's face. The non-patient-contacting surface 3116 may also be in at least partial contact with the plenum chamber 3200.

[0134] The seal-forming structure 3100 of this example also includes a patient-contacting surface 3114. The patient-contacting surface 3114 faces the patient's face in use. The patient-contacting surface 3114 may at least partially seal against the patient's facial skin in use. The patient-contacting surface 3114 is positioned such that the patient's facial skin contacts the patient-contacting surface 3114 in use. The patient's facial skin may contact only a portion of the patient-contacting surface 3114, or the patient's facial skin may contact the entire patient-contacting surface 3114 in use. The patient-contacting surface 3114 may be adjacent to a non-patient-contacting surface 3116. The patient-contacting surface 3114 may also be adjacent to the non-patient-contacting surface 3116.

[0135] The seal-forming structure 3100 of the present example also includes a gas chamber 3120 that is at least partially bounded by the inner surface 3112 of the seal-forming structure 3100. The gas chamber 3120 can be pressurized up to 30 cmH2O by pressurized breathable gas received from the plenum chamber 3200 in use.

[0136] As can be seen from the rear view of Figure 7D, a rear opening 3106 or hole is formed in the patient-contacting surface 3114. Pressurized breathable gas in the gas chamber 3120 of the seal-forming structure 3100 is communicated to the patient's nares through the rear opening 3106. Gas exhaled from the patient's nares is communicated to the gas chamber 3120 through the rear opening 3106 and exhausted via the vent 3400. The rear opening 3106 may be a single opening formed in the patient-contacting surface 3114, or alternatively, the rear opening 3106 may be divided into two separate openings, each communicating with a corresponding nostril of the patient. The rear opening 3106 may be bounded by an edge 3118 of the patient-contacting surface 3114.

[0137] The seal-forming structure 3100 of this example also includes a support structure 3110, as shown in Figures 7C, 7J, and 7M. The support structure 3110 is connected at one end to the front tie 3108, with the connection being with a surface of the front tie 3108 facing the interior of the gas chamber 3120, or facing rearward relative to the seal-forming structure 3100. The other end of the support structure 3110 is connected at an edge 3118 to the patient-contacting surface 3114. As can be seen from the cross-sectional views of Figures 7G-7K and 7M, the top of the patient-contacting surface 3114 of the seal-forming structure 3100 is not supported by the undercushion. The patient-contacting surface 3114 of the seal-forming structure 3100 may be a single layer that engages the patient's nose proximal to the nasal tip. A single layer of the seal-forming structure 3100 in this region may be more flexible compared to a double-wall arrangement (i.e., an arrangement including an undercushion), which may result in a more comfortable and effective seal for a wider range of nose shapes. However, such a single-layer arrangement may be more susceptible to rupture (e.g., pressurized breathable gas causing the patient-contacting surface 3114 of the seal-forming structure 3100 to disengage from the patient's nose). The support structure 3110 counteracts this effect by fastening the edge 3118 of the patient-contacting surface 3114 to another portion of the seal-forming structure 3100.

[0138] The support structure 3110 may also partially contact or be adjacent to the bridge of the patient's nose to prevent the patient's nose from protruding into the gas chamber 3120 of the seal-forming structure 3100. Depending on the size and shape of the patient's individual nose, the support structure 3110 may be adjacent but not directly contacting the bridge of the patient's nose. The support structure 3110 may also support the patient-contacting surface 3114 and bias the patient-contacting surface 3114 into engagement with the patient's nose proximal to the nasal tip to ensure an effective seal. Figure 7J also illustrates, for example, how the support structure 3110 does not cover the rear opening 3106 and does not extend between the upper and lower edges 3118.

[0139] The support structure 3110 may have a different thickness than the patient-contacting surface 3114. The support structure 3110 may be thicker than the patient-contacting surface 3114. The support structure 3110 may have a variable thickness in the longitudinal direction. The support structure 3110 may have an increased thickness adjacent one or both of the locations where the support structure 3110 joins the seal-forming structure 3100.

[0140] 7G, the support structure 3110 forms a continuous loop with the inner surface 3112 of the seal-forming structure 3100 and the forward tie 3108. In another example, the support structure 3110 may be connected to the inner surface 3112 of the seal-forming structure 3100 and not connected to the forward tie 3108. In such another example, the forward tie 3108 may be omitted. The support structure 3110 may have a length in its undeformed state that is greater than the linear distance between the two points where the support structure 3110 connects to the seal-forming structure 3110, providing some slack to the support structure.

[0141] FIG. 7G also shows that the support structure 3110 curves slightly inward into the gas chamber 3120 in its undeformed state. This curved shape may allow the support structure 3110 to better accommodate the patient's nose (including the nasal tip). Alternatively, the support structure 3110 may be straight in its undeformed state in another example. Thus, FIG. 7G shows that the patient-contacting surface 3114 abuts the outer or rear surface of the support structure 3110. In another example, the support structure 3110 may be connected to the inner surface 3112 of the seal-forming structure 3100 opposite the patient-contacting surface 3114 such that an edge 3118 separates the patient-contacting surface 3114 and the support structure 3110.

[0142] The seal-forming structure 3100 (particularly the support structure 3110) may include attributes of the tie 3110 disclosed in International Application Publication No. WO2016 / 149769 (filed March 24, 2016), the entirety of which is incorporated herein by reference.

[0143] The seal-forming structure 3100 may also include an undercushion 3122 that supports a portion of the patient-contacting surface 3114, as shown in Figures 7G-7M. The undercushion 3122 may support only the lower portion of the undercushion 3122. The undercushion 3122 may be provided on only the lower half of the seal-forming structure 3100. The undercushion 3122 in these examples may be configured to support the patient-contacting surface 3114 against the patient's upper lip to ensure an effective seal. A similar undercushion layer 3105 is disclosed in U.S. Provisional Application No. 62 / 328,988, filed April 28, 2016, each of which is incorporated by reference in its entirety.

[0144] The connection region 3102 of the seal-forming structure 3100 may have a shape resembling an infinite loop (∞) or the shape of the number eight (8). It could also be described as having an "hourglass" shape. The connection region 3102 may be shaped such that its narrowest point is at the centerline of the seal-forming structure 3100. The connection region 3102 may then extend upward and downward on both sides away from the centerline, as shown, for example, in FIG. 7B.

[0145] 5.3.2 Plenum chamber The plenum chamber 3200 has edges shaped to complement the surface contours of an average human face in the area where a seal is formed in use. In use, the peripheral edges of the plenum chamber 3200 are positioned in close proximity to the 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 around the entire edge of the plenum chamber 3200 in use. In some forms, the plenum chamber 3200 and the seal-forming structure 3100 are formed from a single, homogenous piece of material.

[0146] In some forms of the present technology, the plenum chamber 3200 does not cover the patient's eye when in use. In other words, the eye is outside the pressurized space defined by the plenum chamber. Such forms may improve treatment compliance, often resulting in less intrusiveness and / or greater wearer comfort.

[0147] In certain forms of the present technology, the plenum chamber 3200 is constructed from a transparent material (e.g., clear polycarbonate). The use of a transparent material may reduce the intrusiveness of the patient interface and may help improve compliance with treatment. The use of a transparent material may help the clinician see the placement and function of the patient interface.

[0148] In certain forms of the present technology, the plenum chamber 3200 is constructed from a translucent material, which can make the patient interface less intrusive and help improve compliance with treatment.

[0149] 5.3.3 Positioning and stabilizing structures The seal-forming structure 3100 of the patient interface 3000 of the present technology may be held in a sealed position by the positioning and stabilising structure 3300 in use.

[0150] In one form, the positioning and stabilizing structure 3300 provides at least enough holding force to overcome the effect of the positive pressure in the plenum chamber 3200 to lift off the face.

[0151] In one form, the positioning and stabilizing structure 3300 provides a holding force sufficient to overcome the attractive force on the patient interface 3000.

[0152] In one form, the positioning and stabilizing structure 3300 provides a holding force as a safety margin to eliminate the possibility of destructive action on the patient interface 3000 (e.g., due to tube drag or inadvertent interference with the patient interface).

[0153] In one form of the present technology, there is provided a positioning and stabilizing structure 3300 configured to be worn by a patient while sleeping. In one example, the positioning and stabilizing structure 3300 has a low profile or cross-sectional thickness to reduce the perceived or actual bulk of the device. In one example, the positioning and stabilizing structure 3300 includes at least one strap having a rectangular cross-section. In one example, the positioning and stabilizing structure 3300 includes at least one flat strap.

[0154] In one form of the present technology, a positioning and stabilizing structure 3300 is provided that is configured so that it is not excessively large or bulky in size that would interfere with a patient sleeping in a supine sleeping position with the posterior region of the patient's head resting on a pillow.

[0155] In one form of the present technology, a positioning and stabilizing structure 3300 is provided that is configured so that it is not excessively large or bulky in size that would interfere with a patient sleeping in a lateral sleeping position with the side region of the patient's head resting on a pillow.

[0156] In one form of the present technology, the positioning and stabilizing structure 3300 comprises a decoupling section located between an anterior section of the positioning and stabilizing structure 3300 and a posterior section of the positioning and stabilizing structure 3300. The decoupling section does not resist compression and can be a flexible or flimsy strap, for example. The decoupling section is constructed and positioned such that when a patient lies down with their head on a pillow, the presence of the decoupling section prevents posterior forces from being transmitted along the positioning and stabilizing structure 3300 and disrupting the seal.

[0157] In one form of the present technology, the positioning and stabilizing structure 3300 includes a strap constructed from a laminate of a fabric patient-contacting layer, a foam material inner layer, and a fabric outer layer. In one form, the foam material is porous to allow moisture (e.g., sweat) to pass through the strap. In one form, the fabric outer layer includes a loop material that engages with a hook material portion.

[0158] In certain forms of the present technology, the positioning and stabilizing structure 3300 includes stretchable (e.g., stretchable with elasticity) straps. For example, the straps can be configured to be tensioned in use to direct a force that seals the seal-forming structure against a portion of the patient's face. In one example, the straps can be configured as ties.

[0159] In one form of the present technology, the positioning and stabilizing structure includes a first tie constructed and arranged such that, in use, at least a portion of its lower edge passes over and moves to a point above the ear base of the patient's head, covering a portion of the parietal bone without covering the occipital bone.

[0160] In one form of the present technology, suitable for a nasal-only or full-face mask, the positioning and stabilizing structure includes a second tie constructed and arranged such that, in use, at least a portion of its upper edge passes below the sub-ear point on the underside of the patient's head and covers or rests below the occipital bone of the patient's head.

[0161] In one form of the present technology suitable for a nasal-only or full-face mask, the positioning and stabilizing structure includes a third tie constructed and arranged to interconnect the first tie and the second tie in a manner that reduces the tendency of the first tie and the second tie to move apart.

[0162] In certain forms of the present technology, the positioning and stabilizing structure 3300 includes straps that are bendable, e.g., non-rigid. An advantage of this embodiment is that the straps are more comfortable when the patient lies down to sleep.

[0163] In a particular form of the present technology, the positioning and stabilizing structure 3300 includes straps configured to be breathable to allow water vapor to pass therethrough.

[0164] In certain forms of the present technology, a system is provided that includes more than one positioning and stabilizing structure 3300. Each positioning and stabilizing structure 3300 is configured to provide a holding force to accommodate a range of different sizes and / or shapes. For example, the system may include one form of positioning and stabilizing structure 3300 that is suitable for large sized heads but not for small sized heads, and another form of positioning and stabilizing structure 3300 that is suitable for small sized heads but not for large sized heads.

[0165] 5.3.4 Ventilation In one form, the patient interface 3000 includes a vent 3400 constructed and arranged to allow the expulsion of exhaled gases (eg, carbon dioxide).

[0166] In certain forms, the vent 3400 is configured to allow continuous vent flow from the interior of the plenum chamber 3200 to atmosphere when the pressure within the plenum chamber is positive relative to atmosphere. The vent 3400 is configured such that the magnitude of the vent flow is sufficient to reduce rebreathing of exhaled CO2 by the patient while maintaining therapeutic pressure within the plenum chamber in use.

[0167] Ventilation section 3400 in one form according to the present technology includes a plurality of holes (eg, about 20 to about 80 holes, or about 40 to about 60 holes, or about 45 to about 55 holes).

[0168] The vent 3400 may be located within the plenum chamber 3200. Alternatively, the vent 3400 is located within a decoupling structure (e.g., a swivel).

[0169] The vent 3400 in the plenum chamber 3200 may include a plurality of openings 3402. The openings 3402 may be arranged in two groups symmetrical about the centerline of the plenum chamber 3200. The plurality of openings 3402 may reduce noise and diffuse ventilation flow concentrations.

[0170] The opening 3402 may be positioned close enough to the centerline of the plenum chamber 3200 so that the opening 3402 is not blocked when the patient is lying down and sleeping. The opening 3402 may be spaced away from the centerline to avoid weakening the chassis in the narrower areas.

[0171] The opening 3402 may have a circular profile.

[0172] 5.3.5 Decoupling Structures (Singular or Plural) 8A, 8B, 9A, and 9B show examples of decoupling structures 3500 in accordance with examples of the present technology. The decoupling structure 3500 may take the form of an elbow. The decoupling structure 3500 may include a swivel 3501 that connects to the air circuit 4170 and a patient interface connector 3502 that connects to the patient interface 3000. The patient interface connector 3502 may allow a tube 3503 of the decoupling structure 3500 to rotate relative to the patient interface 3000. The decoupling structure 3500 may also include a vent 3400. The vent 3400 of the decoupling structure 3500 may include at least one opening 3401 through a portion of the patient interface connector 3502 and / or through a portion of the tube 3503.

[0173] 5.3.6 Connection Port The connection port 3600 allows connection to the air circuit 4170 .

[0174] 5.3.7 Forehead support In one form, the patient interface 3000 includes a forehead support 3700 .

[0175] 5.3.8 Anti-asphyxiation valve In one form, the patient interface 3000 includes an anti-asphyxiation valve.

[0176] 5.3.9 Ports In one form of the present technology, the patient interface 3000 includes one or more ports that allow access to the volume within the plenum chamber 3200. In one form, this allows a clinician to provide supplemental oxygen. In one form, this allows a property of the gas (e.g., pressure) within the plenum chamber 3200 to be directly measured.

[0177] 5.3.10 Patient Interface for the Technology 10 and 11 show a patient interface 3000 according to an example of the present technology. The patient interface 3000 includes a seal-forming structure 3100 according to the example described in section 4.3.1 above. The seal-forming structure 3100 may be connected to a plenum chamber 3200 as described above. The plenum chamber 3200 may be provided with one or more vents 3400.

[0178] The patient interface 3000 may include a positioning and stabilizing structure 3300 that includes a conduit 3301. The purpose of the conduit 3301 is two-fold: 1) to position and stabilize the patient interface 3000 in a therapeutically effective position on the patient's head during use, and 2) to provide pressurized breathable gas to the plenum chamber 3200. To this end, the conduit 3301 may be constructed of a flexible, biocompatible material and may form a hollow structure. The conduit 3301 may be connected to the plenum chamber 3200 by a clip 3303 that clamps the pneumatic connection. The conduit 3301 may also include a strap connector 3302 for connecting to a strap (not shown) that passes behind the patient's head during use. The conduit 3301 may also include a flexible section 3304 that provides flexibility to the conduit 3301 to accommodate different sizes and shapes of patient heads. An elbow connector 3305

[0179] 5.4 RPT Device An RPT device 4000 according to one aspect of the present technology includes mechanical, pneumatic, and / or electrical components and is configured to execute one or more algorithms. The RPT device 4000 can be configured to generate an airflow that is delivered to a patient's airway for treatment of, for example, one or more of the respiratory conditions described anywhere herein.

[0180] In one form, the RPT device 4000 is constructed and arranged to deliver airflow in the range of -20 L / min to +150 L / min while maintaining a positive pressure of at least 6 cmH2O, or at least 10 cmH2O, or at least 20 cmH2O.

[0181] The RPT device may have an outer housing 4010. The outer housing 4010 is formed by two portions: an upper portion 4012 and a lower portion 4014. Additionally, the outer housing 4010 may include one or more panels 4015. The RPT device 4000 includes a chassis 4016 that supports one or more internal components of the RPT device 4000. The RPT device 4000 may include a handle 4018.

[0182] The pneumatic pathway of the RPT device 4000 may include one or more air pathway items and a muffler 4120 (e.g., an inlet air filter 4112, an inlet muffler 4122, a pressure generator 4140 (e.g., a blower 4142) capable of supplying air at positive pressure, an outlet muffler 4124, and one or more transducers 4270 (e.g., a pressure sensor and a flow sensor)).

[0183] One or more of the pneumatic circuit items may be disposed within a removable, unitary structure referred to herein as a pneumatic block 4020. The pneumatic block 4020 may be disposed within the outer housing 4010. In one form, the pneumatic block 4020 is supported by or formed as part of the chassis 4016.

[0184] The RPT device 4000 can have a power supply 4210, one or more input devices 4220, a central controller, a therapy device controller, a pressure generator 4140, one or more protection circuits, a memory, a transducer 4270, a data communication interface, and one or more output devices. The electrical components 4200 can be mounted on a single printed circuit board assembly (PCBA) 4202. In an alternative, the RPT device 4000 can include more than one PCBA 4202.

[0185] 5.4.1 RPT Device Mechanical and Pneumatic Components The RPT device may include one or more of the following components in an integral unit: In an alternative, one or more of the following components may be arranged as their own separate units.

[0186] 5.4.1.1 Air filter(s) An RPT device in accordance with one form of the present technology may include an air filter 4110 or multiple air filters 4110.

[0187] In one form, the inlet air filter 4112 is located at the beginning of the air pressure path upstream of the pressure generator 4140 .

[0188] In one form, an outlet air filter 4114 (eg, an antibacterial agent) is located between the outlet of the pneumatic block 4020 and the patient interface 3000.

[0189] 5.4.1.2 Muffler(s) An RPT device in accordance with one form of the present technology may include a muffler 4120 or multiple mufflers 4120.

[0190] In one form of the present technology, an inlet muffler 4122 is positioned above a pressure generator 4140 in the pneumatic path.

[0191] In one form of the present technology, the outlet muffler 4124 is positioned in the pneumatic path between the pressure generator 4140 and the patient interface 3000.

[0192] 5.4.1.3 Pressure generator In one form of the present technology, the pressure generator 4140 that generates the air flow or supply 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 housed within a volute. The blower may deliver the air supply at a rate of, for example, up to about 120 liters / minute, at a positive pressure ranging from about 4 cmH2O to about 20 cmH2O, or in other forms up to about 30 cmH2O. The blower may be described in any one of the following patents or patent applications, which are incorporated herein by reference in their entirety: U.S. Patent No. 7,866,944; U.S. Patent No. 8,638,014; U.S. Patent No. 8,636,479; and PCT Patent Application Publication WO 2013 / 020167.

[0193] The pressure generator 4140 is under the control of the therapy device controller 4240 .

[0194] In other forms, pressure generator 4140 can be a piston-driven pump, a pressure regulator connected to a high pressure source (eg, a compressed air reservoir), or a bellows.

[0195] 5.4.1.4 Transducer(s) The transducer may be internal to the RPT device or external to the RPT device. An external transducer may, for example, be located on the air circuit or form part of the air circuit (e.g., a patient interface). An external transducer may take the form of a non-contact sensor (e.g., a Doppler radar motion sensor that transmits or moves data RPT device).

[0196] In one form of the present technology, one or more transducers 4270 may be positioned upstream and / or downstream of the pressure generator 4140. The one or more transducers 4270 may be constructed and arranged to generate a signal indicative of a characteristic of the airflow (e.g., flow rate, pressure, or temperature at that point in the pneumatic path).

[0197] In one form of the present technology, one or more transducers 4270 may be positioned proximate the patient interface 3000.

[0198] In one form, the signal from the converter 4270 may be filtered (eg, by low-pass, high-pass, or band-pass filtering).

[0199] 5.4.1.4.1 Flow Sensor A flow sensor according to the present technology may be based on a differential pressure transducer (eg, the SDP600 series differential pressure transducer from SENSIRION).

[0200] In one form, a signal indicative of flow rate from a flow sensor is received by a central controller.

[0201] 5.4.1.4.2 Pressure Sensors A pressure sensor according to the present technology can be placed in fluid communication with the air sensor pressure path. One example of a suitable pressure sensor is a transducer from the HONEYWELL ASDX series. Another suitable pressure sensor is a transducer from the NPA series from GENERAL ELECTRIC.

[0202] In one form, the signal from the pressure sensor may be received by a central controller.

[0203] 5.4.1.4.3 Motor Speed Converter In one form of the present technology, a motor speed transducer may be used to determine the rotational speed of the motor 4144 and / or blower 4142. A motor speed signal from the motor speed transducer may be provided to a therapy device controller. The motor speed transducer may be, for example, a speed sensor (e.g., a Hall effect sensor).

[0204] 5.4.1.5 Anti-spillback valves In one form of the present technology, an anti-spillback valve 4160 may be located between the humidifier 5000 and the pneumatic block 4020. The anti-spillback valve is constructed and positioned to reduce the risk of water flowing upstream from the humidifier 5000 (e.g., to the blower motor 4144).

[0205] 5.4.2 RPT Device Electrical Components 5.4.2.1 Power supply The power supply 4210 may be located inside or outside the external housing 4010 of the RPT device 4000.

[0206] In one form of the present technology, the power supply 4210 powers only the RPT device 4000. In another form of the present technology, power is provided from the power supply 4210 to both the RPT device 4000 and the humidifier 5000.

[0207] 5.4.2.2 Input Devices In one form of the present technology, the RPT device 4000 includes one or more input devices 4220 in the form of buttons, switches, or dials to allow a human to interact with the device. The buttons, switches, or dials may be physical or software devices accessible via a touchscreen. The buttons, switches, or dials may be physically connected to the external housing 4010 in one form, or may communicate wirelessly with a receiver electrically connected to a central controller in another form.

[0208] In one form, input device 4220 may be constructed and arranged to allow a human to select values and / or menu options.

[0209] 5.4.2.3 Central Controller In one form of the present technology, the central controller is one or more processors suitable for controlling the RPT device 4000.

[0210] Suitable processors may include x86 INTEL processors, processors based on the ARM® Cortex®-M processor from ARM Holdings (e.g., the S®32 series of microcontrollers from ST Micro Electronics). In certain alternative forms of the present technology, 32-bit RISC CPUs (e.g., the STR9 series microcontrollers from ST Micro Electronics) or 16-bit RISC CPUs (e.g., processors from the MSP430 family of microcontrollers manufactured by Texas Instruments) may also be suitable.

[0211] In one form of the present technology, the central controller is a dedicated electronic circuit.

[0212] In one form, the central controller is an application specific integrated circuit. In another form, the central controller includes discrete electronic components.

[0213] The central controller may be configured to receive input signal(s) from one or more transducers 4270, one or more input devices 4220 and the humidifier 5000.

[0214] The central controller may be configured to provide output signal(s) to one or more of the output device, the therapy device controller, the data communication interface, and the humidifier 5000.

[0215] In some forms of the present technology, the central controller is configured to implement one or more methods described herein (e.g., one or more algorithms expressed as a computer program stored in a non-transitory computer-readable recording medium (e.g., memory)). In some forms of the present technology, the central controller may be integrated with the RPT device 4000. However, in some forms of the present technology, some methods may be performed by a remotely located device. For example, the remotely located device may determine ventilator control settings or detect respiratory-related events through analysis of recorded data (e.g., from any of the sensors described herein).

[0216] 5.5 Air Circuit An air circuit 4170, according to one aspect of the present technology, is a conduit or tube constructed and arranged such that, in use, air flow travels between two components (e.g., the RPT device 4000 and the patient interface 3000).

[0217] In particular, the air circuit 4170 may be fluidly connected to 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.

[0218] In some forms, the air circuit 4170 may include one or more heating elements configured to heat the air in the air circuit (e.g., to maintain or increase the air temperature). The heating elements may take the form of a heated wire circuit and may include one or more transducers (e.g., temperature sensors). In one form, the heated wire circuit may be spirally wound around the axis of the air circuit 4170. The heating elements may be in communication with a controller (e.g., a central controller). One example of an air circuit 4170 including a heated wire circuit is described in U.S. Patent Application No. 8,733,349, which is incorporated herein by reference in its entirety.

[0219] 5.5.1 Oxygen delivery In one form of the present technology, supplemental oxygen 4180 can be delivered to one or more points in the pneumatic pathway (e.g., upstream of the pneumatic block 4020), the air circuit 4170 and / or the patient interface 3000.

[0220] 5.6 Humidifier 5.6.1 Humidifier Overview In one form of the present technology, a humidifier 5000 is provided (for example as shown in FIG. 5A) for changing the absolute humidity of air or gas to be delivered to a patient relative to the ambient air. Typically, the humidifier 5000 is used to increase the absolute humidity (relative to ambient air) and increase the temperature of the air stream before delivery to the patient's airways.

[0221] The humidifier 5000 may include a humidifier reservoir 5110, a humidifier inlet 5002 for receiving an airflow, and a humidifier outlet 5004 for delivering a humidified airflow. In some forms, such as shown in Figures 5A and 5B, the inlet and outlet of the humidifier reservoir 5110 may be the humidifier inlet 5002 and the humidifier outlet 5004, respectively. The humidifier 5000 may further include a humidifier base 5006. The humidifier base 5006 may be adapted to receive the humidifier reservoir 5110 and may include a heating element 5240.

[0222] 5.6.2 Humidifier Components 5.6.2.1 Water reservoir According to one arrangement, the humidifier 5000 may include a water reservoir 5110 configured to contain or hold a quantity of liquid (e.g., water) to be evaporated for humidifying the air stream. The water reservoir 5110 may be configured to contain a predetermined maximum quantity of water to provide adequate humidification for at least the duration of a respiratory therapy session (e.g., a night's sleep). Typically, the reservoir 5110 is configured to contain several hundred milliliters of water (e.g., 300 milliliters (ml), 325 ml, 350 ml, or 400 ml). In another form, the humidifier 5000 may be configured to receive a water supply from an external water source (e.g., a building's water supply system).

[0223] According to one embodiment, the water reservoir 5110 is configured to humidify the air flow from the RPT device 4000 as the air flow passes through the RPT device 4000. In one form, the water reservoir 5110 can be configured to encourage the air flow to travel a tortuous path through the reservoir 5110 while the air flow contacts a certain amount of water in the reservoir 5110.

[0224] According to one form, the reservoir 5110 may be laterally removable from the humidifier 5000, for example as shown in Figures 5A and 5B.

[0225] The reservoir 5110 may also be configured to inhibit liquid release from the reservoir 5110, for example, when the reservoir 5110 is displaced and / or rotated from its normal operating orientation (e.g., through any aperture and / or between its subcomponents). Because the air stream to be humidified by the humidifier 5000 is often pressurized, the reservoir 5110 may also be configured to prevent loss of air pressure through leakage and / or flow impedance.

[0226] 5.6.2.2 Conductive parts According to one arrangement, the reservoir 5110 includes a conductive region 5120 configured to allow efficient heat transfer from the heating element 5240 to the volume of liquid in the reservoir 5110. In one form, the conductive region 5120 may be arranged as a plate, although other shapes may be suitable. All or part of the conductive region 5120 may be constructed of a thermally conductive material such as aluminum (e.g., approximately 2 mm thick (e.g., 1 mm, 1.5 mm, 2.5 mm, or 3 mm)), another thermally conductive metal, or some plastic. In some cases, adequate thermal conductivity may be achieved with a less conductive material of appropriate geometry.

[0227] 5.6.2.3 Humidifier Reservoir Dock In one form, the humidifier 5000 may include a humidifier reservoir dock 5130 (as shown in FIG. 5B) configured to receive the humidifier reservoir 5110. In some arrangements, the humidifier reservoir dock 5130 may include a locking feature (e.g., a locking lever 5135 configured to retain the reservoir 5110 within the humidifier reservoir dock 5130).

[0228] 5.6.2.4 Water Level Indicator The humidifier reservoir 5110 may include a water level indicator 5150 as shown in Figures 5A-5B. In some forms, the water level indicator 5150 may provide one or more indications to a user, such as the patient 1000 or a caregiver, about the amount of water in the humidifier reservoir 5110. These one or more indications provided by the water level indicator 5150 may include an indication of a maximum predetermined amount of water, any fraction thereof (e.g., 25%, 50%, or 75% or an amount (e.g., 200 ml, 300 ml, or 400 ml)).

[0229] 5.6.2.5 Heating elements In some cases, a heating element 5240 may be provided to the humidifier 5000 to provide heat input to one or more of the volume of water in the humidifier reservoir 5110 and / or the volume of water to the airflow. The heating element 5240 may include a heat-generating component such as an electrical resistance heating track. One suitable example of the heating element 5240 is a layered heating element, for example, as described in PCT Patent Application Publication No. WO2012 / 171072, the entirety of which is incorporated herein by reference.

[0230] In some forms, the heating element 5240 may be mounted in the humidifier base 5006. In the humidifier base 5006, heat may be transferred to the humidifier reservoir 5110 primarily by conduction, as shown in Figure 5B.

[0231] 5.7 Respiratory waveform Figure 6 shows a model of a typical human respiratory waveform during sleep. The horizontal axis is time, and the vertical axis is respiratory flow. Because parameter values can vary, a typical breath may have the following approximate values: tidal volume, Vt, 0.5 L; inspiratory time, Ti, 1.6 seconds; peak inspiratory flow, Qpeak, 0.4 L / sec; expiratory time, Te, 2.4 seconds; peak expiratory flow, Qpeak, -0.5 L / sec. The total duration of the breath, Ttot, is approximately 4 seconds. Humans typically breathe at approximately 15 breaths per minute (BPM), with a ventilation, Vent, of approximately 7.5 L / min. A typical duty cycle, the ratio of Ti to Ttot, is approximately 40%.

[0232] 5.8 Glossary For purposes of this disclosure, in certain aspects of the technology, one or more of the following definitions may apply. In other aspects of the technology, other definitions may apply.

[0233] 5.8.1 General Air: In certain forms of the present technology, air may refer to atmospheric air, while in other forms of the present technology, air may refer to a combination of other breathable gases (e.g., oxygen-rich atmospheric air).

[0234] Atmosphere: In certain forms of the present technology, the term "atmosphere" should be taken to mean (i) that which is external to the treatment system or patient, and (ii) that which immediately surrounds the treatment system or patient.

[0235] For example, the ambient humidity for a humidifier may be the humidity of the air immediately surrounding the humidifier (e.g., the humidity inside the room where the patient is sleeping), which may differ from the humidity outside the room where the patient is sleeping.

[0236] In another example, the ambient pressure may be the pressure immediately surrounding or external to the body.

[0237] In certain embodiments, ambient (e.g., acoustic) noise can be considered the background noise level in the room the patient is in, other than noise emanating from, for example, the RPT device or from the mask or patient interface. Ambient noise can originate from sources outside the room.

[0238] Automatic Positive Airway Pressure (APAP) Therapy: A CPAP therapy that is capable of automatically adjusting therapeutic pressure between minimum and maximum limits, for example, between breaths, depending on the presence or absence of signs of an SDB episode.

[0239] Continuous Positive Airway Pressure (CPAP) Therapy: Respiratory pressure therapy in which the therapeutic pressure is approximately constant throughout the patient's respiratory cycle. In some forms, the pressure at the entrance to the airways increases slightly during exhalation and decreases slightly during inhalation. In some forms, the pressure varies during different respiratory cycles of the patient (e.g., increased in response to the detection of an indication of partial upper airway obstruction and decreased in the absence of notification of partial upper airway obstruction).

[0240] Flow Rate: The instantaneous amount (or mass) of air delivered per unit time. Flow rate can refer to an instantaneous quantity. In some cases, reference to flow rate refers to a scalar quantity (i.e., a quantity that has only magnitude). In other cases, reference to flow rate refers to a vector quantity (i.e., a quantity that has both magnitude and direction). Flow rate may be given the symbol Q. "Flow rate" may also be simply called "flow."

[0241] In the example of a patient's breathing, the flow rate may be nominally positive for the inspiratory portion of the patient's breathing cycle, and therefore negative for the expiratory portion of the patient's breathing cycle. Total flow rate Qt is the flow rate of air exiting the RPT device. Vent flow rate Qv is the flow rate of air exiting the vent to allow for the outflow of exhaled gases. Leakage flow rate Ql is the flow rate of leakage from the patient interface system or elsewhere. Respiratory flow rate Qr is the flow rate of air received into the patient's respiratory system.

[0242] Humidifier: The word "humidifier" is construed to mean a humidifying device constructed, arranged, or configured with a physical structure capable of providing a therapeutically beneficial amount of water (H2O) vapor to an air stream to improve the medical respiratory condition of a patient.

[0243] Leak: The term "leak" refers to unintended airflow. In one example, a leak can occur due to an imperfect seal between the mask and the patient's face. In another example, a leak can occur at the elbow to the perimeter.

[0244] Noise Conduction (Acoustic): In this document, conducted noise refers to noise carried to the patient by the pneumatic path (e.g., the air circuit and patient interface and the air therein). In one form, conducted noise can be quantified by measuring the sound pressure level at the end of the air circuit.

[0245] Noise Emission (Acoustic): In this document, radiated noise refers to noise carried by the ambient air to the patient. In one form, radiated noise can be quantified by measuring the sound power / pressure level of the target in accordance with ISO 3744.

[0246] Ventilation noise (acoustic): In this document, ventilation noise refers to the noise generated by airflow through any ventilation (eg, ventilation holes in the patient interface).

[0247] Patient: A person with or without a respiratory disease.

[0248] Pressure: Force per unit area. Pressure can be expressed and measured in a variety of units (e.g., cmH2O, gf / cm 2 , and hectopascals). 1cmH2O is 1g-f / cm 2 which is approximately 0.98 hectopascals. In this specification, pressures are given in units of cmH2O unless otherwise specified.

[0249] The pressure in the patient interface is designated by the symbol Pm, and the therapeutic pressure, which represents the target value that the mask pressure Pm should achieve at this time, is designated by the symbol Pt.

[0250] Respiratory Pressure Therapy (RPT): The application to the airway entrance of an air supply at therapeutic pressure, typically positive pressure relative to atmosphere.

[0251] Ventilator: A mechanical device that provides pressure support to a patient while they perform some or all of the work of breathing.

[0252] 5.8.1.1 Materials Silicone or silicone elastomer: Synthetic rubber. References to silicone herein refer to liquid silicone rubber (LSR) or compression molded silicone rubber (CMSR). One commercially available form of LSR is SILASTIC (a product family sold under this trademark) manufactured by Dow Corning. Another LSR manufacturer is Wacker. Unless otherwise specified, exemplary forms of LSR have a Shore A (or Type A) indentation hardness of about 35 to about 45, as measured by ASTM D2240. (Year? Required?)

[0253] Polycarbonate: A thermoplastic polymer of bisphenol A carbonate.

[0254] 5.8.1.2 Mechanical properties Elasticity: The ability of a material to absorb energy during elastic deformation and to release the energy when unloaded.

[0255] Elastic: Releases substantially all of the energy upon unloading. Examples include certain silicone and thermoplastic elastomers.

[0256] Hardness: The ability of a material to resist deformation (e.g., as described by Young's modulus or the indentation hardness scale measured on a standardized sample size). "Soft" materials may include silicone or thermoplastic elastomers (TPEs) and may easily deform under finger pressure, for example. "Hard" materials may include polycarbonate, polypropylene, steel or aluminum, and do not easily deform under finger pressure, for example.

[0257] Stiffness (or rigidity) of a structure or component: The ability of a structure or component to resist deformation when subjected to a load. The load can be a force or a moment (e.g., compression, extension, bending, or torsion). A structure or component may offer different resistance in different directions.

[0258] Floppy structure or component: A structure or component that changes shape (e.g., flexes) within a relatively short period of time (e.g., 1 second) when forced to support its own weight.

[0259] Rigid structure or component: A structure or component that does not substantially change shape when subjected to loads typically encountered in use. An example of such an application would be setting up and maintaining a patient interface in a sealed manner against a patient's airway entrance under a pressure load of, for example, approximately 20-30 cmH2O.

[0260] As one example, an I-beam may have a different bending stiffness (resistance to bending load) in a first direction compared to a second, orthogonal direction. In another example, a structure or component may be floppy in a first direction and rigid in a second direction.

[0261] 5.8.2 Breathing cycle Apnea: According to some definitions, apnea is said to occur when flow below a predetermined threshold continues for a duration of, for example, 10 seconds. Obstructive apnea is said to occur when some airway obstruction does not allow airflow despite patient effort. Central apnea is said to refer to a condition in which apnea is detected due to reduced or absent respiratory effort despite a patent airway. Mixed apnea is said to refer to a condition in which reduced or absent respiratory effort occurs simultaneously with airway obstruction.

[0262] Respiratory rate: The patient's spontaneous breathing rate, usually measured in breaths per minute.

[0263] Duty cycle: The ratio of inspiration time Ti to total breathing time Ttot.

[0264] Exercise (Respiration): Respiratory effort is said to refer to the movement made by the spontaneous breathing of a person trying to breathe.

[0265] Expiratory portion of the respiratory cycle: the period from the start of expiratory flow to the start of inspiratory flow.

[0266] Flow limitation: Flow limitation is understood to be a condition in a patient's breathing where an increase in patient effort does not result in a corresponding increase in flow rate. If flow limitation occurs during the inspiratory portion of the respiratory cycle, the flow limitation can be referred to as inspiratory flow limitation. If flow limitation occurs during the expiratory portion of the respiratory cycle, the flow limitation can be referred to as expiratory flow limitation.

[0267] Flow-limited inspiration waveform types: (i) Flattening: An upswing followed by a relatively flat area, followed by a downswing. (ii) M-shaped: has two local peaks, one at the rise and one at the fall, with a relatively flat region between these two peaks. (iii) Chair-like: A single local peak occurs at the rising part, followed by a relatively flat region. (iv) Inverted chair: A relatively flat region is followed by a single local peak, which occurs on the trailing edge.

[0268] Hypopnea: By some definitions, hypopnea refers to a reduction in flow, rather than an interruption of flow. In one form, hypopnea is said to occur when flow is reduced below a threshold rate for a sustained period of time. When hypopnea is detected due to a decrease in respiratory effort, central hypopnea is said to occur. In one form, hypopnea may be considered when any of the following occur in adults: (i) A 30% decrease in patient respiration for at least 10 seconds plus an associated 4% desaturation, or (ii) A reduction in patient respiration (less than 50%) lasting at least 10 seconds and associated desaturation of at least 3% or arousal occurs.

[0269] Hyperventilation: An increase in flow to a level higher than normal.

[0270] Inspiratory portion of the respiratory cycle: The period from the start of the inspiratory flow to the start of the expiratory flow is taken as the inspiratory portion of the respiratory cycle.

[0271] Patency (Airway): The degree to which the airway is open or the extent to which it is open. Airway patency is an opening. Airway patency can be quantified, for example, with a value of 1 indicating open and a value of 0 indicating closed (obstructed).

[0272] Positive end-expiratory pressure (PEEP): The pressure above atmosphere in the lungs that exists at the end of expiration.

[0273] Peak flow (Qpeak): The maximum value of flow during the inspiratory portion of the respiratory flow waveform.

[0274] Respiratory airflow, airflow, patient airflow, respiratory airflow (Qr): These terms may be understood to refer to the RPT device's estimate of respiratory airflow, and are used in contrast to "true respiratory flow" or "true respiratory airflow," which is the patient's actual respiratory flow, usually expressed in liters / minute.

[0275] Tidal Volume (Vt): The volume of air inhaled or exhaled during normal breathing without extra effort.

[0276] (Inspiration) Time (Ti): The duration of the inspiratory portion of the respiratory flow waveform.

[0277] (Expiratory) Time (Te): The duration of the expiratory portion of the respiratory flow waveform.

[0278] (Total) Time (Ttot): The total duration between the start of one inspiratory portion of the respiratory flow waveform and the start of the next inspiratory portion of the respiratory flow waveform.

[0279] Typical Recent Ventilation: The ventilation value around which recent values of ventilationVent over a given time scale tend to cluster (i.e., the degree to which recent values of ventilation tend to be centered).

[0280] Upper Airway Obstruction (UAO): Includes both partial and total upper airway obstruction. May be associated with a state of flow limitation in which flow may increase or decrease slightly with increasing pressure differential across the upper airway (Starling resistor behavior).

[0281] Vent: A measure of the rate of gas exchange performed by a patient's respiratory system. Measurements of ventilation may include either or both inspiratory and expiratory flow per unit time. When expressed as volume per minute, this quantity is often referred to as "minute ventilation." Minute ventilation is sometimes given simply as volume and is understood as volume per minute.

[0282] 5.8.3 Ventilation Adaptive servo-ventilator (ASV): A servo-ventilator that does not have a fixed target ventilation but is variable. The variable target ventilation can be learned from some characteristic of the patient (e.g., the patient's breathing characteristics).

[0283] Backup Rate: A ventilator parameter that establishes the minimum respiratory rate (typically in breaths per minute) that will be delivered to the patient by the ventilator (when not triggered by spontaneous breathing efforts).

[0284] Cycle: The end of the inspiratory phase of a ventilator. When a ventilator delivers breaths to a spontaneously breathing patient, at the end of the inspiratory portion of the breathing cycle, the ventilator is said to be cycled to stop breath delivery.

[0285] Expiratory Positive Airway Pressure (EPAP): The base pressure to which varying pressures are added within a breath to produce the desired mask pressure that the ventilator attempts to achieve at a given moment.

[0286] End Expiratory Pressure (EEP): The desired mask pressure that the ventilator attempts to achieve at the end of the expiratory portion of the breath. If the pressure waveform template Π(Φ) has a value of zero at the end of expiration (i.e., Π(Φ)=0 when Φ=1), then EEP is equal to EPAP.

[0287] Inspiratory Positive Airway Pressure (IPAP): The maximum desired mask pressure that the ventilator attempts to achieve during the inspiratory portion of the breath.

[0288] Pressure Support: A number indicating the increase in pressure during ventilator inspiration compared to the corresponding ventilator expiration, and refers primarily to the pressure difference between the maximum inspiratory pressure and the base pressure (e.g., PS = IPAP - EPAP). In some contexts, pressure support refers to the difference the ventilator attempts to achieve (rather than the difference it actually achieves).

[0289] Servo-ventilator: A ventilator that has both patient ventilation and target ventilation, and adjusts the level of pressure support to bring the patient ventilation closer to the target ventilation.

[0290] Spontaneous / Timed (S / T): A mode of a ventilator or other device that attempts to detect the onset of a breath in a spontaneously breathing patient. However, if the device fails to detect a breath within a predetermined period of time, the device automatically begins breath delivery.

[0291] Swing: A term equivalent to pressure assistance.

[0292] Triggered: When a ventilator delivers a breath of air to a spontaneously breathing patient, the ventilator is said to be triggered to deliver a breath when the patient himself initiates the breathing portion of the breathing cycle.

[0293] Typical Recent Ventilation: Typical recent ventilation Vtyp is a range of values around which recent ventilation measurements tend to cluster over a given time scale. For example, a measure of the central tendency of ventilation measurements over recent history may be an appropriate value for typical recent ventilation.

[0294] 5.8.4 Anatomy 5.8.4.1 Facial Anatomy Alar: the outer wall or "wing" of each nostril (plural: alar)

[0295] Alar angle:

[0296] Alare: The outermost point on the ala of the nose.

[0297] Alar curvature (or alar crest) point: The most posterior point on the curved baseline of each alar, found in the crease formed by the union of the alar and cheek.

[0298] Pinna: the entire visible part of the ear.

[0299] (Nasal) skeleton: The nasal skeleton includes the nasal bones, the frontal process of the maxilla, and the nasal portion of the frontal bone.

[0300] (Nasal) cartilaginous rami: The cartilaginous rami of the nose include the septal cartilage, lateral cartilage, greater cartilage, and lesser cartilage.

[0301] Columella: The piece of skin that separates the nostrils and extends from the tip of the nose to the upper lip.

[0302] Columella angle: the angle between a line drawn through the midpoint of the nostril and a line drawn perpendicular to the Frankfurt horizontal and intersecting the subnasal point.

[0303] Frankfort horizontal plane: A line extending from the most inferior point of the orbital rim to the left auricular point, which is the deepest point of the auricle from the superior side of the notch to the tragus.

[0304] Glabellar: Located in the soft tissue, the most prominent point in the midsagittal direction of the forehead.

[0305] Lateral nasal cartilage: a generally triangular plate of cartilage whose upper margin is attached to the nasal bone and the frontal process of the maxilla, and whose lower margin is connected to the greater alar cartilage.

[0306] Lip, lower side (lower lip: labrale inferius):

[0307] Lip, upper side (upper lip: labrale superius):

[0308] Greater alar cartilage: a cartilaginous plate located beneath the lateral nasal cartilage. It curves around the anterior part of the nostril. Its posterior end is connected to the frontal process of the maxilla by a tough fibrous membrane containing three or four alar cartilages.

[0309] Nostrils (alae): Generally ellipsoidal alar openings that form the entrance to the nasal cavity. The singular form of nostril is nostril (alae). These nostrils are separated by the nasal septum.

[0310] Nasolabial fold or nasolabial crease: a fold or groove of skin that extends from each side of the nose to the corners of the mouth, separating the cheek from the upper lip.

[0311] Nasolabial angle: the angle between the bridge of the nose and the upper lip, intersecting with the subnasal point.

[0312] Subbasal point of the ear: the lowest point of attachment of the pinna to the facial skin.

[0313] Suprabasal point of the ear: the highest point of attachment of the pinna to the facial skin.

[0314] Nasal tip: The most prominent point or tip of the nose, which can be seen in a lateral view of the rest of the head.

[0315] Philtrum: midline groove extending from the lower border of the nasal septum to the top of the lip in the upper lip area.

[0316] Pogonion: The most anterior midpoint of the jaw, located on the soft tissue.

[0317] Nasal ridge: The nasal ridge is the midline prominence of the nose, extending from the serion to the apex.

[0318] Sagittal plane: a vertical plane running from anterior (front) to posterior (back) that divides the body into right and left halves.

[0319] Cerion: Located on the soft tissue, it is the most concave point on the area of the frontonasal suture.

[0320] Septal cartilage (nose): The nasal septum cartilage is part of the septum, which divides the anterior part of the nasal cavity.

[0321] Nasal alar nasal basin: the point on the lower periphery of the alar base where it joins with the skin of the upper (top) lip.

[0322] Subnasal point: Located on the soft tissue, the point where the columella joins the upper lip in the midsagittal plane.

[0323] Supramenton: The most concave point in the midline of the lower lip between the lower lip midpoint and the soft tissue pogonion.

[0324] 5.8.4.2 Skull anatomy Frontal bone: The frontal bone contains the squama frontalis, a large vertical portion that corresponds to the area known as the forehead.

[0325] Mandible: The mandible forms the lower jaw. The mental protuberance is a bony protuberance in the jaw that forms the chin.

[0326] Maxilla: The maxilla forms the upper jaw and is located below the mandible and below the orbit. The frontal process of the maxilla projects upward by the sides of the nose and forms part of its lateral border.

[0327] Nasal bones: The nasal bones are two small, rectangular bones that vary in size and shape from person to person. They lie side by side in the middle and upper parts of the face, and their junction forms the "bridge" of the nose.

[0328] Nasion: the intersection of the frontal bone and the two nasal bones, a concave area directly between the eyes and the upper side of the bridge of the nose.

[0329] Occipital bone: The occipital bone is located at the back and underside of the skull. It contains the foramen magnum, an oval hole through which the intracranial cavity connects with the vertebral canal. The curved plate posterior to the foramen magnum is the squama occipitalis.

[0330] Orbit: bony cavity in the skull that contains the eyeball.

[0331] Parietal bones: The parietal bones are bones that, when joined together, form the top and sides of the skull.

[0332] Temporal bone: The temporal bone is located on the base and sides of the skull and supports parts of the face known as the temples.

[0333] Cheekbones: The two cheekbones in the face are located in the upper and outer parts of the face and form the cheek ridges.

[0334] 5.8.4.3 Respiratory system anatomy Diaphragm: A sheet of muscle that runs over the lower rib cage. The diaphragm separates the thoracic cavity, which contains the heart, lungs, and ribs, from the abdominal cavity. When the diaphragm contracts, it increases the volume of the thoracic cavity and draws air into the lungs.

[0335] Larynx: The larynx or voice box that houses the vocal cords and connects the lower part of the pharynx (hypopharynx) to the trachea.

[0336] Lung: respiratory organ in humans. The conductive zone of the lung includes the trachea, bronchi, bronchi, and terminal bronchioles. The respiratory zone includes the respiratory bronchioles, alveolar ducts, and alveoli.

[0337] Nasal Cavity: The nasal cavity (or nasal fossa) is a large, air-filled space in the center of the face above and behind the nose. The nasal cavity is divided into two by a vertical fin called the nasal septum. The sides of the nasal cavity contain three horizontal extensions called turbinates or nasal conchae. The nasal cavity opens anteriorly into the nose and posteriorly into the nasopharynx via the choanae.

[0338] Pharynx: The part of the throat located immediately below (inferior to) the nasal cavity and above the esophagus and larynx. The pharynx is traditionally divided into three parts: the nasopharynx (upper pharynx) (nasal part of the pharynx), the oropharynx (mid pharynx) (oral part of the pharynx), and the hypopharynx (low pharynx).

[0339] 5.8.5 Patient Interface Anti-asphyxiation valve (AAV): A component or subassembly of a mask system that vents to atmosphere in a fail-safe manner to reduce the risk of excessive CO2 rebreathing by the patient.

[0340] An elbow is an example of a structure that directs the axis of airflow moving therethrough to change direction through an angle. In one form, the angle may be approximately 90 degrees. In another form, the angle may be greater than or less than 90 degrees. The elbow may have a generally circular cross-section. In another form, the elbow may have an oval or rectangular cross-section. In certain forms, the elbow may be rotatable relative to the mating component, for example, approximately 360 degrees. In certain forms, the elbow may be detachable from the mating component, for example, via a snap connection. In certain forms, the elbow may be assembled to the mating component via a one-time snap during manufacturing, but cannot be removed by the patient.

[0341] Frame: Frame is taken to mean the mask structure that supports the tensile load between two or more points that connect the headgear. A mask frame can be a non-airtight load-bearing structure in the mask. However, some forms of mask frames may be airtight.

[0342] Functional Dead Space: (insert description here)

[0343] Headgear: Headgear is taken to mean a form of positioning and stabilizing structure designed for use on the head. For example, the headgear may include a collection of one or more posts, ties, and stiffeners configured to position and hold the patient interface in place on the patient's face for delivery of respiratory therapy. Some ties are formed from a soft, flexible, elastic material (e.g., a layered composite of foam and fabric).

[0344] Membrane: Membrane is taken to mean a typically thin-walled element, preferably substantially non-resistant to bending and resistant to stretching.

[0345] Plenum Chamber: Mask plenum chamber is taken to mean a part of a patient interface having walls that at least partially enclose a volume of space, the air in the volume being pressurized to exceed atmospheric pressure in use. The shell may form part of the wall of the mask plenum chamber.

[0346] Seal: When used as a noun ("seal"), it can refer to a structure, and when used as a verb ("to seal"), it can refer to an effect. Two elements can be constructed and / or arranged to "seal" or achieve a "sealing" effect between them without the need for a separate "sealing" element itself.

[0347] Shell: A shell is taken to mean a curved, relatively thin structure that has bending, tensile, and compressive stiffness. For example, the curved structural wall of a mask may be a shell. In some forms, the shell may be faceted. In some forms, the shell may be airtight. In some forms, the shell may not be airtight.

[0348] Stiffener: A stiffener is taken to mean a structural component designed to increase the bending resistance of another component in at least one direction.

[0349] Strut: A strut is taken to mean a structural component designed to increase the compressive resistance of another component in at least one direction.

[0350] Swivel (noun): A subassembly of components configured to rotate, preferably independently, about a common axis, preferably under low torque. In one form, the swivel may be configured to rotate through an angle of at least 360 degrees. In another form, the swivel may be configured to rotate through an angle less than 360 degrees. When used in the context of an air delivery conduit, the subassembly of components preferably includes a mating cylindrical conduit. In use, there is little leakage of air flow from the swivel.

[0351] Tie (noun): A structure designed to resist tension.

[0352] Venting: (noun): A structure that allows airflow into the ambient atmosphere inside a mask or conduit, allowing clinically effective flushing of exhaled gases. For example, for clinically effective flushing, flow rates of about 10 liters / minute to about 100 liters / minute may be used depending on mask design and treatment pressure.

[0353] 5.8.6 Structural Shape Products of the present technology may include one or more three-dimensional mechanical structures (e.g., a mask cushion or impeller). The three-dimensional structures may be bounded by two-dimensional surfaces. These surfaces may be distinguished using labels to describe the orientation, location, function, or some other characteristic of the associated surfaces. For example, the structure may include one or more of a front surface, a back surface, an interior surface, and an exterior surface. In another example, the seal-forming structure may include a face-contacting (e.g., outer) surface and a separate non-face-contacting (e.g., lower or interior) surface. In another example, the structure may include a first surface and a second surface.

[0354] To facilitate the description of the shape and surface of a three-dimensional structure, we first consider a cross section at a point p through the surface of the structure. See Figures 3B-3F. Figures 3B-3F show an example cross section at point p on the surface and an example of the resulting planar curve. Figures 3B-3F also show the outward normal vector at p. The outward normal vector at p points away from the surface. In some examples, the surface is described from the perspective of a fictitious little person standing upright on the surface.

[0355] 5.8.6.1 Curvature in one dimension The curvature of a plane curve at p can be described as having a sign (eg, positive, negative) and a magnitude (eg, 1 / radius of the circle tangent to the curve at p).

[0356] Positive curvature: If the curve at p bends toward the outward normal, the curvature at that point is taken to have a positive value (if our fictitious little person were to walk away from point p, they would have to walk uphill). See Figure 3B (relatively large positive curvature compared to Figure 3C) and Figure 3C (relatively small positive curvature compared to Figure 3B). Such curves are often called concave.

[0357] Zero curvature: If the curve at p is a straight line, the curvature is taken as zero (if this imaginary little person walks away from point p, they can walk on a horizontal plane that is neither pointing up nor pointing down). See Figure 3D.

[0358] Negative curvature: If the curve at p bends away from the outward normal, the curvature at that point and in that direction is taken to have a negative value (if this fictitious little person were to walk away from point p, they would have to walk downhill). See Figure 3E (relatively small negative curvature compared to Figure 3F) and Figure 3F (relatively large negative curvature compared to Figure 3E). Such curves are often called convex.

[0359] 5.8.6.2 Two-dimensional surface curvature A description of a shape at a given point on a two-dimensional surface according to the present technology may include multiple perpendicular cross sections. The multiple cross sections may cut the surface in a plane containing the outward normal (the "normal plane"), and each cross section may be taken in a different direction. Each cross section results in a plane curve with a corresponding curvature. The different curvatures at the point may have the same or different signs. Each curvature at the point has a (e.g., relatively small) magnitude. The plane curves in Figures 3B-3F may be examples of such multiple cross sections at a particular point.

[0360] Principal curvature and direction: The directions of the normal plane in which the curvature of a curve reaches its maximum and minimum values are called the principal directions. In the example of Figures 3B-3F, the maximum curvature occurs in Figure 3B and the minimum occurs in Figure 3F, so Figures 3B and 3F are cross sections in the principal directions. The principal curvature at p is the curvature in the principal direction.

[0361] Surface region: A set of connected points on a surface. This set of points within a region may have similar properties (e.g., curvature or sign).

[0362] Saddle region: A region where the principal curvatures at each point have opposite signs (i.e., one positive sign and the other negative sign) (depending on the direction a hypothetical person who may be walking uphill or downhill is facing).

[0363] Dome area: an area where the principal curvatures at each point have the same sign: either both positive ("concave dome") or both negative ("convex dome")

[0364] Cylindrical region: A region in which one principal curvature is zero (or, for example, zero within manufacturing tolerances) and the other principal curvature is non-zero.

[0365] Planar region: A region of a surface where both principal curvatures are zero (or are zero within a manufacturing tolerance, for example).

[0366] Surface Edge: The boundary or limit of a surface or area.

[0367] Path: In certain forms of the present technology, a "path" is taken to mean a path in the mathematical-topological sense (e.g., a continuous space curve from f(0) to f(1) on a surface). In certain forms of the present technology, a "path" may be described as a route or course that includes, for example, a set of points on a surface. (A hypothetical person's path is a place they walk on a surface, similar to a path in a garden.)

[0368] Path Length: In certain forms of the present technology, "path length" is taken to refer to the distance along the surface from f(0) to f(1) (i.e., the distance along a path on the surface). There may be more than one path between two points on the surface, and such paths may have different path lengths. (The path length of a fictional person is the distance walked along the path on the surface.)

[0369] Straight-line distance: Straight-line distance is the distance between two points on a surface, but does not take the surface into account. On a planar area, there is a distance on the surface edge that has the same path length as the straight-line distance between two points on the surface. On a non-planar surface, there cannot be a path that has the same path length as the straight-line distance between two points. (For a fictional person, straight-line distance corresponds to the distance as the crow flies.)

[0370] 5.8.6.3 Space curve Space Curve: Unlike a plane curve, a space curve does not necessarily exist within any particular plane. A space curve may be closed, i.e., it has no endpoint. A space curve may be considered a one-dimensional piece of three-dimensional space. A fictional character walking on a strand of DNA helix walks along a space curve. A typical human left ear contains a left-handed helix (see Figure 3Q). A typical human right ear contains a right-handed helix (see Figure 3R). Figure 3S shows a right-handed helix. The edge of a structure (e.g., the edge of a membrane or impeller) may trace a space curve. In general, a space curve can be described by the curvature and twist at each point on the space curve. Torsion is a measure of the way the curve emanates from the plane. Twist has a sign and a magnitude. The twist at a point on a space curve can be characterized with respect to the tangent, normal, and binormal vectors at that point.

[0371] Tangent unit vector (or unit tangent vector): For each point on a curve, the vector at that point specifies the direction and magnitude from that point. A tangent unit vector is a unit vector that points in the same direction as the curve at that point. If a fictional character were flying along the curve and fell off their vehicle at a particular point, the direction of the tangent vector would be the direction they would be traveling.

[0372] Unit normal vector: As the fictional character moves along the curve, this tangent vector itself changes. The unit vector that points in the same direction as the tangent vector is changing is called the unit principal normal vector. It is perpendicular to the tangent vector.

[0373] Binormal unit vector: The binormal unit vector is perpendicular to both the tangent vector and the principal normal vector. Its direction can be determined by the right-hand rule (see, for example, Figure 3P) or the left-hand rule (Figure 3O).

[0374] Oscillating plane: A plane containing a unit tangent vector and a unit principal normal vector. See Figures 3O and 3P.

[0375] Torsion of a Space Curve: The torsion at a point on a space curve is the magnitude of the rate of change of the binormal unit vector at that point. It measures the degree of deviation of the curve from the tangential plane. A space curve that lies within a plane has zero torsion. If the space curve deviates from the tangential plane by a relatively small amount, the magnitude of torsion of the space curve is relatively small (e.g., a gently sloping spiral path). If the space curve deviates from the tangential plane by a relatively large amount, the magnitude of torsion of the space curve is relatively large (e.g., a steeply sloping spiral path). Referring to Figure 3S, because T2 > T1, the magnitude of torsion near the top coil of the spiral in Figure 3S is greater than the magnitude of torsion of the bottom coil of the spiral in Figure 3S.

[0376] Referring to the right-hand rule in Figure 3P, a space curve that bends toward the right-hand binormal can be considered to have a positive right-hand twist (e.g., a right-hand spiral as shown in Figure 3S). A space curve that bends away from the right-hand binormal can be considered to have a negative right-hand twist (e.g., a left-hand spiral).

[0377] Similarly, with reference to the left-hand rule (see Figure 3O), a space curve oriented in a left-handed binormal direction can be considered as having a positive left-handed twist (e.g., a left-handed spiral). Thus, a positive left-handed direction corresponds to a negative right-handed direction. See Figure 3T.

[0378] 5.8.6.4 Holes A surface may have one-dimensional holes (e.g., holes bounded by a planar or space curve). In the case of a thin structure (e.g., a membrane) that contains holes, the structure may be described as having one-dimensional holes. See, for example, how the one-dimensional holes in the surface of the structure shown in Figure 3I are bounded by a planar curve.

[0379] A structure can have a two-dimensional hole (e.g., a hole bounded by a surface). For example, an inflatable tire has a two-dimensional hole bounded by the tire's inner surface. In another example, a bladder with a cavity for air or gel can have a two-dimensional hole. See, for example, the cushion in FIG. 3L and the exemplary cross-section of FIG. 3L in FIGS. 3M and 3N, where the inner surface bounding the two-dimensional hole is shown. In yet another example, a conduit can include a one-dimensional hole (e.g., at its inlet or its outlet) and can include a two-dimensional hole bounded by the inner surface of the conduit. See also the two-dimensional hole through the structure shown in FIG. 3K and bounded by a surface as shown.

[0380] 5.9 Other Notes A portion of the disclosure of this patent document contains material that is entitled to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of this patent document or this patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but reserves all copyright rights therefor for all other purposes.

[0381] Unless otherwise clearly indicated from the context and unless 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 limits of the range, and for any other stated or intervening value in the stated range, is encompassed by the technology. The upper and lower limits of these intervening ranges, independently included in the intervening range, are also encompassed by the technology if they specifically exceed the limits in the stated range. If the stated range includes one or both of these limits, then ranges exceeding either or both of these stated limits are also encompassed by the technology.

[0382] Furthermore, when a value or values are embodied herein as part of the present technology, unless otherwise specified, it is understood that such values may be approximated and may be used to any appropriate significant figures to the extent practical technical practice permits or requires.

[0383] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of this technology, a limited number of exemplary methods and materials are described herein.

[0384] Although particular materials are described as being suitable for use in the construction of components, obvious alternative materials having similar properties may be substituted. Furthermore, unless stated to the contrary, any and all components described herein are understood to be manufacturable and therefore may be manufactured collectively or separately.

[0385] Please note 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.

[0386] All publications mentioned herein are incorporated by reference to disclose and describe the methods and / or materials that are the subject of these publications. The publications mentioned herein are provided solely for their disclosure prior to the filing date of this application. Nothing herein should be construed as an admission that the present technology does not antedate such publications by virtue of prior patents. Furthermore, the dates of publications mentioned may differ from the actual publication dates, which may require independent confirmation.

[0387] The terms "comprises" and "comprising" should be construed as referring to elements, components, or steps in a non-exclusive sense, indicating that a described element, component, or step may be present in, utilized with, or combined with other elements, components, or steps not specifically described.

[0388] The headings used in the detailed description are for the convenience of the reader and should not be used to limit the content found in the disclosure or claims as a whole. These headings should not be used in interpreting the scope of the claims or the claim limitations.

[0389] Although the technology herein has been described with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the technology. In some cases, terms and symbols may indicate specific details unnecessary for the practice of the technology. For example, although the terms "first" and "second" (etc.) are used, unless otherwise specified, these terms are not intended to indicate any order but are used to distinguish between separate elements. Furthermore, although the process steps in the method may be described or illustrated in an ordered manner, such an order is not required. Those skilled in the art will recognize that such an order can be changed and / or aspects can be performed simultaneously or even synchronously.

[0390] It is therefore to be understood that numerous modifications may be made in the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present technology. [Explanation of symbols]

[0391] 5.10 List of Reference Symbols 1000 patients 1100 Bedmate 3000 Patient Interface 3100 Seal forming structure 3102 Connection Area 3104 Front opening 3106 Rear opening 3108 Front tie 3110 Support Structure 3112 Interior 3114 Patient Contact Surface 3116 Non-Patient Contact Surface 3118 Edge 3120 Gas Chamber 3122 Undercushion 3200 Plenum Chamber 3210 Tendon 3220 Upper point 3230 Down 3300 Positioning and Stabilizing Structures 3301 Conduit 3302 Strap Connector 3303 clips 3304 Flexible part 3305 Elbow Connector 3400 Ventilation section 3401 Opening 3402 Opening 3500 Uncoupling structure 3501 Swivel 3502 Patient Interface Connector 3503 Tube 3600 connection port 3700 Forehead support 4000 RPT devices 4010 Outer Housing 4012 Upper 4014 Lower 4015 Panel 4016 chassis 4018 Handle 4020 Pneumatic Block 4110 Air Filter 4112 Inlet Air Filter 4114 Outlet air filter 4120 Muffler 4122 Inlet muffler 4124 Exit muffler 4140 Pressure Generator 4142 Blower 4144 Motor 4160 Anti-spillback valve 4170 Air Circuit 4180 Supplemental Oxygen 4200 Electrical Components 4202 PCBA 4210 Power supply 4220 input devices 4270 Converter 5000 humidifier 5002 Humidifier inlet 5004 Humidifier outlet 5006 Humidifier Base 5110 Reservoir 5120 Conductive parts 5130 Humidifier Reservoir Dock 5135 Lock lever 5150 Water Level Indicator 5240 heating element

Claims

1. 1. A patient interface comprising: At least 6 cmH above ambient air pressure ２ a plenum chamber pressurizable to a therapeutic pressure of O, said plenum chamber including a plenum chamber inlet port sized and configured to receive a flow of air at the therapeutic pressure for breathing by a patient; a seal-forming structure constructed and arranged to form a seal against an area of the patient's face surrounding an entrance to the patient's airway, said seal-forming structure constructed and arranged to, in use, maintain said therapeutic pressure within the plenum chamber throughout the patient's respiratory cycle; a positioning and stabilizing structure that provides a force to hold the seal-forming structure in a therapeutically effective position on the patient's head, said positioning and stabilizing structure including a tie, the tie constructed and arranged such that, in use, at least a portion of the tie rests against a region of the patient's head above the supra-ear point; a venting structure that allows a continuous flow of gases exhaled by a patient from within the plenum chamber to the surroundings, the venting structure being sized and shaped to maintain the therapeutic pressure within the plenum chamber in use; the patient interface is configured to allow the patient to breathe from atmosphere through their oral cavity in the absence of pressurized air flow through the plenum chamber inlet port, or alternatively, the patient interface is configured to leave the patient's oral cavity exposed; the seal-forming structure further includes a patient-contacting surface configured to engage and form a seal with the patient's facial skin, and a rear opening formed in the patient-contacting surface, the rear opening configured to provide the airflow at the treatment pressure to the patient's nares; A patient interface, wherein the seal-forming structure includes a support structure extending from a first location on the patient-contacting surface to a second location on an inner surface of the seal-forming structure, the support structure and the inner surface forming a continuous loop.

2. the seal-forming structure further includes a front opening formed in the non-patient-contacting surface and a front tie covering the front opening; The patient interface of claim 1 , wherein a first end of the support structure is connected to the front tie.

3. the seal-forming structure further includes an edge bounding the rear opening in the patient-contacting surface; The patient interface of claim 2 , wherein a second end of the support structure is connected to the patient contacting surface at an upper region of the rim.

4. A patient interface according to any preceding claim, wherein the support structure has a length in an undeformed state that is greater than the linear distance from the first position to the second position.

5. A patient interface according to any preceding claim, wherein the support structure is configured, in use, to be positioned in contact with or adjacent the bridge of the patient's nose.

6. A patient interface according to any preceding claim, wherein the support structure is curved along a longitudinal axis of the support structure in an undeformed state.

7. A patient interface according to any preceding claim, wherein the support structure has a different thickness than the patient contacting surface.

8. A patient interface according to any preceding claim, wherein the support structure is thicker than the patient contacting surface.

9. A patient interface according to any preceding claim, wherein the support structure does not extend entirely through the rear opening.

10. the seal-forming structure at least partially defines a gas chamber; A patient interface according to any preceding claim, wherein the support structure extends into the gas chamber in an undeformed state.

11. A patient interface according to any preceding claim, wherein the support structure has a variable thickness in the longitudinal direction.

12. A patient interface according to any preceding claim, wherein the support structure has an increased thickness adjacent the first location and / or the second location.

13. A patient interface according to any preceding claim, wherein a portion of the support structure is curved along a longitudinal axis of the support structure in an undeformed state.

14. A patient interface according to any preceding claim, wherein the seal-forming structure further comprises an undercushion supporting the patient-contacting surface.

15. 15. The patient interface of claim 14, wherein a lower portion of the seal-forming structure includes the undercushion and an upper portion of the seal-forming structure does not include the undercushion.

16. 15. The patient interface of claim 14, wherein the undercushion is structured to support the patient contacting surface only against the patient's upper lip.

17. 1. A seal-forming structure for a patient interface, said seal-forming structure constructed and arranged to form a seal with an area of a patient's face surrounding an entrance to said patient's airway, said seal-forming structure providing a pressure of at least 6 cmH above ambient air pressure throughout said patient's respiratory cycle in use. ２ constructed and arranged to maintain a therapeutic pressure of O within the plenum chamber, said seal-forming structure comprising: a patient-contacting surface configured to engage and form a seal with the patient's facial skin; a rear opening formed in the patient-contacting surface, the rear opening configured to provide airflow at the treatment pressure to the patient's nares; a support structure extending from a first location on the patient-contacting surface to a second location on an inner surface of the seal-forming structure, the support structure and the inner surface forming a continuous loop; The patient interface is configured to allow the patient to breathe from atmosphere through their oral cavity in the absence of pressurized air flow through the plenum chamber inlet port, or alternatively, the patient interface is configured to leave the patient's oral cavity exposed.

18. further comprising a front opening formed in the non-patient-contacting surface and a front tie covering the front opening; The seal-forming structure of claim 17 , wherein a first end of the support structure is connected to the forward tie.

19. and further comprising an edge bounding the posterior opening in the patient-contacting surface.

20. The seal-forming structure of claim 18, wherein a second end of the support structure is connected to the patient-contacting surface at an upper region of the rim.

20. A seal-forming structure according to any one of claims 17 to 19, wherein the support structure has a length in an undeformed state that is longer than the linear distance from the first position to the second position.

21. A seal-forming structure according to any one of claims 17 to 20, wherein the support structure is configured to be positioned in contact with or adjacent the bridge of the patient's nose in use.

22. A seal-forming structure according to any one of claims 17 to 21, wherein the support structure is longitudinally curved in an undeformed state.

23. A seal-forming structure according to any one of claims 17 to 22, wherein the support structure has a different thickness than the patient-contacting surface.

24. A seal-forming structure according to any one of claims 17 to 23, wherein the support structure is thicker than the patient-contacting surface.

25. A seal-forming structure according to any one of claims 17 to 24, wherein the support structure does not extend entirely across the rear opening.

26. the seal-forming structure at least partially defines a gas chamber; A seal-forming structure according to any one of claims 17 to 25, wherein the support structure, in an undeformed state, extends into the gas chamber.

27. A seal-forming structure according to any one of claims 17 to 26, wherein the support structure has a variable thickness in the longitudinal direction.

28. A seal-forming structure according to any one of claims 17 to 27, wherein the support structure has an increased thickness adjacent the first location and / or the second location.

29. A seal-forming structure according to any one of claims 17 to 28, wherein a portion of the support structure is curved along a longitudinal axis of the support structure in an undeformed state.

30. 30. The seal-forming structure of any one of claims 17 to 29, further comprising an undercushion supporting the patient-contacting surface.

31. 31. The seal-forming structure of claim 30, wherein a lower portion of the seal-forming structure includes the undercushion and an upper portion of the seal-forming structure does not include the undercushion.

32. 32. The seal-forming structure of claim 31, wherein the undercushion is structured to support the patient-contacting surface only against the patient's upper lip.

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