Ventilation system for patient interface

Abstract

The vent structure may include a vent housing including an inlet, an outlet, at least one exhaust gas orifice, and a membrane having spaced-apart first and second ends, the membrane having a movable portion between the first and second ends. The movable portion may be radially spaced from a membrane-facing surface inside the vent housing to form an exhaust gas flow path therebetween, allowing exhaust gas from the pressurized volume to flow through the exhaust gas flow path and through the exhaust gas orifice to the atmosphere. The movable portion may be elastically deformable and configured to move radially relative to the membrane-facing surface in response to a pressure differential between the inside and outside of the membrane, thereby changing the cross-sectional area of ​​the exhaust gas flow path and regulating vent gas flow.

Description

[Technical Field]

[0001] 1 Cross-reference to related applications This application claims priority to U.S. Provisional Application No. 62 / 810,640, filed February 26, 2019, 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 screening, diagnosing, monitoring, treating, preventing, and ameliorating 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 primary function of the lungs 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 the conducting airways and do not participate in gas exchange. The airways further divide into the respiratory bronchioles and ultimately the alveoli. Gas exchange occurs in the alveolar region of the lung, which is called the respiratory region. 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. This is the result of an abnormally small upper airway combined with the 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 as many as 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 nervous 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 abnormal 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 therapeutic systems or devices. Such systems and devices may also be used to screen, diagnose, or monitor a 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 reduced compliance, 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. However, if the mask is uncomfortable or difficult to use, patients may not comply. Patients are often encouraged to clean their masks regularly, but 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 effect 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 to 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 individually or as part of a system to implement one or more of the above-mentioned therapies, for example, by actuating the device to generate a flow of air delivered to an interface with the airway. 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 of noise output levels of conventional RPT devices (measured on one sample only at 10cmH2O in CPAP mode using the test method specified in ISO3744). [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 Elis Accent-Aiguée® 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 comfort of the patient's airway. 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 one or more "compliance rules" with 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 out exhaled carbon dioxide, which may allow gas 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 vent may include an orifice 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 and bed companion, 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] Conventional mask noise table (ISO17510-2:2007, 10cmH2O pressure at 1m) [Table 2]

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

[0070] The sound pressure values ​​of various objects are listed below [Table 3]

[0071] 2.2.4 Screening, diagnostic, and surveillance systems Polysomnography (PSG) is a conventional system for diagnosing and monitoring cardiopulmonary diseases, but it typically requires specialized clinical staff for system application. PSG typically involves placing 15–20 contact sensors on the human 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. Screening, diagnosing, and monitoring sleep-disordered breathing is particularly unsuitable for home use.

[0072] In general, screening and diagnosis involve identifying disease through signs and symptoms. Screening typically produces a true / false result indicating whether a patient's SDB warrants further investigation, while diagnosis often produces clinically actionable information. Screening and diagnosis tend to be one-time procedures, whereas monitoring the progression of disease can continue indefinitely. While some screening / diagnostic systems are adapted solely for screening / diagnosis, some can also be used for monitoring.

[0073] A clinical expert may adequately screen, 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. [Prior art documents] [Patent documents]

[0074] [Patent Document 1] U.S. Patent No. 6,532,959 [Patent Document 2] U.S. Patent No. 4,782,832 Summary of the Invention [Means for solving the problem]

[0075] 3. Brief description of the technology The present technology relates to the provision of medical devices for use in screening, diagnosing, monitoring, ameliorating, treating or preventing respiratory diseases, which medical devices have one or more of improved comfort, cost, effectiveness, ease of use and manufacturability.

[0076] A first aspect of the present technology relates to devices used in the screening, diagnosis, monitoring, amelioration, treatment or prevention of respiratory disease.

[0077] Another aspect of the present technology relates to methods used in the screening, diagnosis, monitoring, amelioration, treatment or prevention of respiratory disorders.

[0078] An aspect of certain forms of the present technology is to provide methods and / or devices that improve patient compliance with respiratory therapy.

[0079] 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.

[0080] One aspect of one form of the present technology is a portable RPT device that can be carried by a person (e.g., around the home).

[0081] One aspect of one form of the present technology is a medical device that can be cleaned in the patient's home, for example with soapy water, without the need for special cleaning equipment.

[0082] Another aspect of the present technology relates to a patient interface for providing respiratory therapy to a patient using a therapeutic gas flow pressurized above atmospheric pressure, and a venting system configured to vent the gas flow from a volume within the patient interface to atmosphere, the gas flow being vented to atmosphere continuously throughout the patient's respiratory cycle.

[0083] Another aspect of the present technology relates to a ventilation system (e.g., used by a respiratory pressure therapy device) for use in conjunction with a patient interface to provide respiratory therapy to a patient using a therapeutic gas flow pressurized above ambient pressure throughout the patient's respiratory cycle. The ventilation system is configured to release the ventilation gas flow to ambient. The ventilation flow can be continuous throughout the patient's respiratory cycle. The ventilation system includes a ventilation housing having a first end and a second end aligned along a longitudinal axis of the ventilation housing, and at least one exhaust gas orifice configured to release exhaust gas to ambient. A membrane disposed within the vent housing, the membrane having a first end, a second end, and a movable portion, the first end of the membrane and the second end of the membrane being spaced apart along a longitudinal axis of the membrane aligned with the longitudinal axis of the vent housing, the movable portion of the membrane being spaced apart radially from a membrane-facing surface inside the vent housing to form an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface, the exhaust gas flow path being configured to allow exhaust gas to flow from the volume through the exhaust gas flow path and through at least one exhaust gas orifice to the atmosphere in use.

[0084] 3.1 Ventilated structure with inlet, outlet and exhaust gas orifices Another aspect of the present technology relates to a ventilation system for use with a patient interface to provide respiratory therapy to a patient using a therapeutic gas flow pressurized above ambient pressure within a therapeutic pressure range. The therapeutic gas flow may be pressurized by a respiratory pressure therapy device and provided to the patient throughout the patient's respiratory cycle. The ventilation system may be configured to provide a ventilation gas flow for releasing exhaust gases exhaled by the patient from the pressurized volume. The ventilation gas flow may be continuous throughout the patient's respiratory cycle. The ventilation system may include a ventilation housing including: an inlet configured to receive the gas flow from the respiratory pressure therapy device, an outlet configured to supply the therapeutic gas flow to the patient interface, and at least one exhaust gas orifice configured to release the exhaust gases to ambient. The at least one exhaust gas orifice is sized and shaped to maintain a therapeutic pressure in the plenum chamber in use; and a membrane disposed within the vent housing, the membrane having a first end and a second end spaced apart along a longitudinal axis of the membrane, the membrane having a movable portion disposed between the first end and the second end of the membrane and surrounding the longitudinal axis. The movable portion of the membrane may be radially spaced apart from the longitudinal axis of the membrane from a membrane-facing surface on the interior side of the vent housing, thereby forming an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface, the exhaust gas flow path being configured to allow gas from the volume to flow through the exhaust gas flow path and through the at least one exhaust gas orifice to the atmosphere in use. The movable portion of the membrane may be elastically deformable and configured to move radially relative to the membrane-facing surface in response to a pressure differential between the inside and outside of the membrane, thereby varying the cross-sectional area of ​​the exhaust gas flow path and regulating vent gas flow throughout a therapeutic pressure range.

[0085] According to another aspect of the present technology, there is provided a patient interface comprising: a plenum chamber at least partially defining a volume that is pressurizable in use to a therapeutic pressure of at least 6 cmH2O above ambient air pressure throughout the patient's respiratory cycle, said plenum chamber including a plenum chamber inlet port sized and configured to receive a therapeutic gas flow for breathing of the patient; a seal-forming structure constructed and arranged to seal against an area of ​​the patient's face surrounding an entrance to the patient's airways, said seal-forming structure having holes therein whereby said therapeutic gas flow is delivered to at least entrances to the patient's nares in use, said seal-forming structure constructed and arranged to maintain said therapeutic pressure within the plenum chamber throughout the patient's respiratory cycle; a positioning and stabilizing structure configured to hold said seal-forming structure in a therapeutically effective position on the patient's head; and a venting structure configured to exhaust the venting gas flow to atmosphere throughout the patient's respiratory cycle.The venting structure includes a venting housing including an inlet configured to receive a gas flow from a respiratory pressure therapy device, an outlet configured to provide a therapeutic gas flow to a plenum chamber inlet port, and at least one exhaust gas orifice configured to release a vent gas flow to the atmosphere, the at least one exhaust gas orifice sized and shaped to maintain a therapeutic pressure in the plenum chamber in use; and a membrane disposed within the venting housing, the membrane having a first end and a second end spaced apart along a longitudinal axis of the membrane, the membrane having a movable portion disposed between the first end and the second end of the membrane and surrounding the longitudinal axis, the movable portion of the membrane moving radially relative to the longitudinal axis of the membrane inside the venting housing. a movable portion of the membrane configured to move radially relative to the membrane facing surface in response to a pressure differential between the inside and outside of the membrane to vary a cross-sectional area of ​​the exhaust gas flow path and regulate ventilation gas flow throughout a therapeutic pressure range; and a patient interface 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, to leave the patient's oral cavity exposed.

[0086] In examples of the above embodiment, (a) the movable portion of the membrane may be substantially cylindrical or frustoconical; the movable portion of the membrane may be substantially cylindrical; (c) the vent housing may include a first end and a second end aligned along a longitudinal axis of the vent housing, the longitudinal axis of the membrane being aligned with the longitudinal axis of the vent housing; (d) the longitudinal axis of the membrane may be aligned substantially parallel to a direction of gas flow through the vent housing from the first end of the vent housing to the second end of the vent housing; (e) the movable portion of the membrane may be aligned with the first end of the vent housing. (f) the movable portion of the membrane may include one or more walls aligned parallel to the direction of gas flow through the vent housing from the first end of the vent housing to the second end of the vent housing; (g) the vent structure may include a membrane support that supports the membrane; (h) the membrane may be joined to the membrane support at the first end of the membrane; (i) the membrane support may be configured to connect to the vent housing; (j) the membrane may include a support member that supports the membrane; the movable portion may be formed from silicone rubber; (k) the vent housing may include a first housing member at a first end of the vent housing and a second housing member at a second end of the vent housing, the first housing member and the second housing member being configured to be connected together; (l) the first housing member may include an inlet connection configured to fluidly connect the vent structure to a supply conduit; (m) the inlet connection may be provided at or near a first end of the first housing portion; (n) the inlet connection may include a bayonet fitting configured to engage with a corresponding fitting on the supply conduit; (o) the second housing member may include an outlet connection configured to fluidly connect the vent structure to a patient interface or to a tube configured to be connected to a patient interface; (p) the outlet connection may be configured to connect to a patient interface or a tube configured to be connected to a patient interface; (q) the outlet connection may include internal threads configured to engage with corresponding threads on the patient interface or patient interface tubing;and / or (r) the exhaust gas flow path may occupy a continuous space all around within the vent housing;

[0087] In further example embodiments, (a) the vent structure may include a damping structure configured to damp vibrations of the movable portion of the membrane; (b) the damping structure may include a damping chamber within the vent housing configured to damp vibrations of the movable portion of the membrane; (c) the vent housing may at least partially form the damping chamber; (d) one of the inside and outside of the movable portion of the membrane may face the membrane-facing surface, and the other of the inside and outside of the movable portion of the membrane may at least partially form the damping chamber; and (e) the damping chamber may have a pressurized volume and a flow rate in use. (f) the venting structure may be configured such that movement of the movable portion of the membrane increases or decreases the volume of the damping chamber; (g) the venting housing and the damping chamber may be configured to damp vibrations of the movable portion of the membrane by restricting gas exchange between the damping chamber and the pressurized volume; (h) the venting structure may include at least one damping orifice through which gas from the pressurized volume can flow into and out of the damping chamber, the damping orifice being configured to restrict or decrease the volume of the damping chamber. (i) the vent structure may include a plurality of damping orifices through which gas from the pressurized volume flows into and out of the damping chamber, the plurality of damping orifices together allowing gas to exchange between the damping chamber and the pressurized volume; (j) the exhaust gas flow path may include a region having a smaller cross-sectional area than adjacent regions of the exhaust gas flow path; (k) the exhaust gas flow path may include a restriction that defines a region having a smaller cross-sectional area than adjacent regions; (l) the membrane-facing surface may be closest to the movable portion of the membrane at the location of the restriction; (m (a) the membrane-facing surface may include a constriction that forms a restriction in the exhaust gas flow path; (n) the membrane-facing surface may include a contoured surface that forms the constriction; (o) the constriction may include a rib in the membrane-facing surface; (p) the constriction may include a region of increased material thickness; (q) the constriction may be centrally located between a first end of the membrane and a second end of the membrane; (r) the damping chamber may include a first end adjacent to the first end of the membrane and a second end adjacent to the second end of the membrane, the restriction in the exhaust gas flow path being centrally located between the first end of the damping chamber and the second end of the damping chamber;(s) the vent housing may be configured to reduce vibration of the movable portion of the membrane in vibration modes higher than the primary vibration mode; (t) the damping chamber may be further defined by one or more walls of the second housing member; and / or (u) the damping chamber may be further defined by one or more walls of the membrane support;

[0088] In further examples of the above embodiment, (a) the vent housing can be configured to restrict movement of the movable portion of the membrane toward the membrane-facing surface; (b) the vent housing can be configured to contact the edge of the membrane and prevent the edge of the vent membrane from moving toward the membrane-facing surface; (c) the vent housing can include at least one protrusion, which is configured to contact the edge of the membrane and restrict movement of the edge of the membrane toward the membrane-facing surface; (d) the at least one protrusion can be positioned outside the exhaust gas flow path; and / or (e) the vent housing can include a plurality of protrusions and a plurality of damping orifices between the protrusions, which provide passages for gas to flow from the volume into and out of the damping chamber. The damping orifices resist gas exchange between the damping chamber and the volume to damp vibration of the movable portion of the membrane.

[0089] In further example embodiments, (a) the ventilation gas flow may flow in a radial direction at or near the inlet to the exhaust gas flowpath; (b) the ventilation gas flow may change direction from a radial direction to an axial direction aligned with a longitudinal axis of the ventilation structure as it passes through the inlet to the exhaust gas flowpath; (c) the vent housing may include a rounded surface at or near the inlet to the exhaust gas flowpath; (d) the rounded surface may facilitate changing the direction of the ventilation gas flow at or near the inlet to the exhaust gas flowpath; (e) the vent housing may include a rounded surface at or near the inlet to the exhaust gas flowpath; (f) the exhaust gas orifices may be spaced apart around the periphery of the vent housing; (g) the vent housing may include at least one diffused exhaust gas orifice and at least one non-diffused exhaust gas orifice; (h) the vent housing may include a plurality of diffused exhaust gas orifices and a plurality of non-diffused exhaust gas orifices; (i) at least one diffused exhaust gas orifice and at least one non-diffused exhaust gas orifice. (j) the diffusing exhaust gas orifices may be located at or near a first end of the vent housing; (k) the non-diffusing exhaust gas orifice may be centrally located between the first end of the vent housing and the second end of the vent housing; (l) the at least one diffusing exhaust gas orifice may open in a lateral direction; (m) the at least one non-diffusing exhaust gas orifice may open partially toward the second end of the vent housing in a direction oblique to the lateral direction; (n) the vent structure may include a diffuser member configured to diffuse and / or muffle gases in contact with the diffuser member in use; (o) the diffuser member may be located in series with the at least one diffusing exhaust gas orifice such that gases flowing in the at least one diffusing exhaust gas orifice are required to flow through the diffuser member; (p) the vent structure may provide a diffusing ventilation flow path. The diffusive ventilation flow path may allow ventilation of gases through the diffuser member and at least one diffusive exhaust gas orifice; (q) the ventilation structure may provide a non-diffusive ventilation flow path.The non-diffusional ventilation flow path may allow ventilation of gas through at least one non-diffusional exhaust gas orifice; (r) the ventilation structure may be configured to allow gas flow through the at least one non-diffusional exhaust gas orifice when the gas cannot pass through the at least one diffused exhaust gas orifice; (s) the ventilation structure may be shaped to require more redirection of the gas flow through the at least one non-diffusional exhaust gas orifice than through the diffused exhaust gas orifice; and / or (t) the ventilation structure may be shaped to require a redirection of the gas flow through the non-diffusional exhaust gas orifice to a sufficient extent that a majority of the exhaust gas flow passes through the diffuser member and the diffused exhaust gas aperture unless the diffuser member becomes clogged.

[0090] In further examples of the above embodiment, (a) the ventilation structure may include an exhaust gas orifice member including at least one exhaust gas orifice; (b) the exhaust gas orifice member may include a plurality of exhaust gas orifices; (c) the exhaust gas orifice member may be configured to connect to the first housing member; (d) the exhaust gas orifice member may be formed in a ring shape; (e) the exhaust gas orifice member may include a plurality of exhaust gas orifices spaced apart around a periphery of the ring; (f) at least (g) at least one diffusing exhaust gas orifice may be provided at or near a first end of the exhaust gas orifice member; (h) at least one non-diffusing exhaust gas orifice may be provided at or near a second end of the exhaust gas orifice member opposite the first end of the exhaust gas orifice member; (i) the diffuser member may be held within the ventilation structure by the exhaust gas orifice member; and / or (ii) the diffuser member may be housed between the exhaust gas orifice member and the first housing member.

[0091] In further examples of the above aspects, (a) the movable portion of the membrane may be disposed radially outward from the membrane-facing surface relative to a longitudinal axis of the membrane; (b) the movable portion of the membrane may be configured to move inward to restrict vent gas flow; (c) the movable portion of the membrane may be configured to contract to move radially inward toward the membrane-facing surface; (d) the membrane-facing surface may be provided on an outer surface of the first housing member, the outer surface being disposed within the vent housing; (e) the first housing member may include a shaft configured to protrude from a first end of the first housing member into the interior of the vent structure, the membrane-facing surface being provided on an outer surface of the shaft at or near a second end of the first housing member; (f) the shaft may be configured to extend from a first end of the first housing member into the interior of the vent structure. (g) the shaft may be aligned with the longitudinal axis of the vent housing; (h) the rounded surface may be a fillet on the outer periphery of the first housing member at or near the inlet to the exhaust gas flow path; (i) the rounded surface may be provided on the shaft at the second end of the first housing member; (j) the vent housing may include a plurality of protrusions, and a plurality of damping orifices may be defined between the plurality of protrusions; (k) at least one protrusion may be provided on the second housing member; (l) the at least one protrusion may be disposed inwardly of the membrane; (m) the at least one protrusion may protrude into the first end of the vent housing; (n) the second housing member may include an inwardly extending membrane stop flange.On this inwardly extending membrane stop flange, at least one protrusion projects axially into the first end of the vent housing; (o) the at least one protrusion may contact an inner surface of the membrane at the second end of the membrane; (p) the first housing member may include an outwardly extending flange on the shaft located at or near the first end of the first housing member; (q) the exhaust gas orifice member may be configured to connect to an outwardly extending flange on the first housing member opposite the second end of the first housing member; (r) the membrane support member may include a connector for connection to the vent housing; (s) the connector may be configured to connect directly or indirectly to the vent housing; (t) the connector may be cylindrically shaped and configured to fit around the exterior of the second housing member; (u) the connector (v) the membrane support may include a membrane support flange formed as a flange extending inward from the interior of the connection portion of the membrane support; (w) the membrane may be molded to the membrane support flange; (x) the membrane support flange may be spaced apart from the end of the connection portion; (y) the exhaust gas orifice member and the membrane support may be configured to be connected together to connect the first housing member and the second housing member; (z) the connection portion of the membrane support may be configured to connect to the exhaust gas orifice member; (aa) the connection portion of the membrane support may be configured to be press-fit onto the outside of the exhaust gas orifice member; and / or (bb) when the membrane support is connected to both the exhaust gas orifice member and the second housing member, the membrane support flange may be positioned between the exhaust gas orifice member and the second housing member.

[0092] In further examples of the above embodiment, (a) the movable portion of the membrane may be supported inwardly of the membrane-facing surface; (b) the movable portion of the membrane may be configured to move outwardly to restrict vent gas flow; (c) the movable portion of the membrane may be configured to expand and move outwardly toward the membrane-facing surface; (d) the membrane-facing surface may be provided on an inner surface of the first housing member; (e) the membrane-facing surface may be cylindrical or frustoconical; (f) the membrane support may include a baffle portion; (g) the baffle portion may be cylindrical; (h) the baffle portion may be concentric with the movable portion of the membrane; (i) the baffle portion may be positioned adjacent to the membrane-facing surface. (j) the baffle portion may have a first end connected to the movable portion of the membrane at the first end of the membrane and a second end provided at or adjacent the second end of the membrane; (k) the baffle portion may include an outwardly extending flange at the second end of the baffle portion; (l) the rounded surface may be a fillet provided on the second end support of the membrane at or adjacent the entrance to the exhaust gas flow path; (m) the rounded surface may be provided on an outwardly extending flange of the baffle portion of the membrane support; (n) the damping chamber is partially filled by the baffle portion of the membrane support. (o) the damping chamber may be defined in part by an outwardly extending flange of the baffle portion; (p) the at least one protrusion may be provided on the first housing member; (q) the at least one protrusion may protrude radially inward from the cylindrical or conical surface of the first housing member; (r) the at least one protrusion may contact an outer surface of the membrane at the second end of the membrane; (s) the first housing member may include at least one intermediate exhaust gas orifice upstream of the diffuser member; (t) the diffuser member may be substantially cylindrical in shape. (u) the second housing member may include a diffuser retainer; (v) the diffuser retainer may include a cylindrical sleeve configured to fit over the first housing member; (w) the first housing member may be substantially cylindrical, the second housing member connection portion provided at the second end of the first housing member, and the diffuser support flange provided at the second end of the first housing member;(x) a diffuser may be retained in the diffuser flow passage between the diffuser support flange of the first housing member, the second housing member connecting portion of the first housing member, and the diffuser retainer of the second housing member; (y) at least one exhaust gas orifice may be provided in the diffuser retainer of the second housing member or may be formed by a gap between the diffuser retainer of the second housing member and the diffuser support flange of the first housing member; and / or (z) a plurality of exhaust gas orifices may be provided in the diffuser retainer of the second housing member and / or in a gap between the diffuser retainer of the second housing member and the diffuser support flange of the first housing member;

[0093] 3.2 Vent structure configured to limit movement of the second end of the movable membrane Another aspect of the present technology relates to a ventilation system for use with a patient interface to provide respiratory therapy to a patient using a therapeutic gas flow pressurized above atmospheric pressure within a therapeutic pressure range. The therapeutic gas flow may be pressurized by a respiratory pressure therapy device and may be provided throughout the patient's respiratory cycle. The ventilation system may be configured to provide a ventilation gas flow from a pressurized volume for releasing exhaled gases by the patient. The ventilation gas flow may be continuous throughout the patient's respiratory cycle. The ventilation system may include a ventilation housing. The vent housing includes at least one exhaust gas orifice configured to allow exhaust gas to be released from the pressurized volume to the atmosphere; and a membrane disposed within the vent housing, the membrane having a first end and a second end spaced apart along a longitudinal axis of the membrane, the membrane having a movable portion disposed between the first end and the second end of the membrane and surrounding the longitudinal axis, the movable portion of the membrane being radially spaced apart from a membrane-facing surface on the inside of the vent housing relative to the longitudinal axis of the membrane to form an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface, the exhaust gas flow path being configured to allow exhaust gas to flow from the pressurized volume through the exhaust gas flow path to the atmosphere via the at least one exhaust gas orifice during use. The movable portion of the membrane can be elastically deformable and configured to move radially relative to the membrane-facing surface in response to a pressure differential between an inside of the membrane and an outside of the membrane to vary the cross-sectional area of ​​the exhaust gas flow path and regulate ventilation gas flow throughout a therapeutic pressure range. The vent housing can be configured to limit movement of the second end of the membrane toward the membrane-facing surface.

[0094] According to another aspect of the present technology, there is provided a patient interface comprising: a plenum chamber at least partially defining a volume that is pressurizable in use to a therapeutic pressure of at least 6 cmH2O above ambient air pressure throughout a patient's respiratory cycle, said plenum chamber including a plenum chamber inlet port sized and configured to receive a therapeutic gas flow from the volume for breathing of the patient; a seal-forming structure constructed and arranged to seal against an area of ​​the patient's face surrounding an entrance to the patient's airways, said seal-forming structure having holes therein whereby said therapeutic gas flow is delivered to at least entrances to the patient's nares in use, said seal-forming structure constructed and arranged to maintain said therapeutic pressure within the plenum chamber throughout the patient's respiratory cycle; a positioning and stabilizing structure configured to hold said seal-forming structure in a therapeutically effective position on the patient's head; and a venting structure configured to exhaust the venting gas flow to atmosphere throughout the patient's respiratory cycle.The venting structure includes a venting housing including at least one exhaust gas orifice for gas release to atmosphere, the at least one exhaust gas orifice sized and shaped to maintain a therapeutic pressure in the plenum chamber in use; and a membrane disposed within the venting housing, the membrane having a first end and a second end spaced apart along a longitudinal axis of the membrane, the membrane having a movable portion disposed between the first end and the second end of the membrane and surrounding the longitudinal axis; The movable portion of the membrane is radially spaced from the membrane-facing surface inside the vent housing relative to the longitudinal axis of the membrane to form an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface, the exhaust gas flow path being configured to allow exhaust gas to flow from the pressurized volume through the exhaust gas flow path to atmosphere via at least one exhaust gas orifice in use; the movable portion of the membrane is elastically deformable and configured to move radially relative to the membrane-facing surface in response to a pressure differential between the inside of the membrane and the outside of the membrane, thereby changing the cross-sectional area of ​​the exhaust gas flow path and regulating ventilation gas flow throughout a therapeutic pressure range; the first end of the membrane is fixed in a predetermined position within the vent housing, the vent housing being configured to restrict movement of the second end of the membrane toward the membrane-facing surface; 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.

[0095] In examples of the above embodiment, (a) the vent housing may contact the second end of the membrane and prevent the second end of the membrane from moving toward the membrane-facing surface; (b) the vent housing may include at least one protrusion configured to contact the second end of the membrane and limit movement of the second end of the membrane toward the membrane-facing surface; (c) the movable portion of the membrane may be substantially cylindrical or frustoconical; (d) the vent housing may include a first end and a second end aligned along a longitudinal axis, the longitudinal axis of the membrane being aligned with the longitudinal axis of the vent housing; (e) the longitudinal axis of the membrane may move through the vent housing from the first end of the vent housing to the second end of the vent housing. (f) the movable portion of the membrane may include one or more wall portions aligned parallel to the direction of gas flow through the vent housing from the first end of the vent housing to the second end of the vent housing; (g) the movable portion of the membrane may include a cylindrical wall portion with an axis aligned parallel to the direction of gas flow through the vent housing from the first end of the vent housing to the second end of the vent housing; (h) the vent structure may include a membrane support portion supporting the membrane. (i) the membrane may be joined to a membrane support at a first end of the membrane; (j) the membrane support may be configured to be connected to the vent housing; (k) the movable portion of the membrane may be formed from silicone rubber; (l) the vent housing may include an inlet device for receiving gas flow from the respiratory pressure therapy device and an outlet for supplying therapeutic gas flow to the patient interface; (m) the vent housing may include a first housing member at a first end of the vent housing and a second housing member at a second end of the vent housing, the first housing member and the second housing member being configured to be connected together; (n) the first housing member may include an inlet and an inlet connection configured to fluidly connect the vent structure to a supply conduit; (o) the inlet connection may be provided at or near a first end of the first housing portion; (p) the inlet connection may include a bayonet fitting configured to engage a corresponding fitting on the supply conduit;(q) the second housing member may include an outlet and an outlet connection configured to fluidly connect the vent structure to a patient interface; (r) the outlet connection may be configured to connect to a patient interface or a tube configured to connect to a patient interface; (s) the outlet connection may include internal threads configured to engage with corresponding threads on the patient interface or a tube configured to connect to a patient interface; and / or (t) the exhaust gas flow path may occupy a continuous space all around within the vent housing;

[0096] In further example embodiments, (a) the vent structure may include a damping structure configured to damp vibrations of the movable portion of the membrane; (b) the damping structure may include a damping chamber within the vent housing; (c) the vent housing may at least partially form the damping chamber; (d) one of the inside and outside of the movable portion of the membrane may face the membrane-facing surface, and the other of the inside and outside of the movable portion of the membrane may at least partially form the damping chamber; (e) the damping chamber may be in fluid communication with a pressurized volume in use; and (f) the vent structure may be configured to move the damping chamber with the movement of the movable portion of the membrane. (g) the venting housing and the damping chamber may be configured to damp vibrations of the moving part of the membrane by restricting gas exchange between the damping chamber and the pressurized volume; (h) the venting structure may include at least one damping orifice through which gas from the pressurized volume can flow into and out of the damping chamber, the damping orifice resisting gas exchange between the damping chamber and the pressurized volume; (i) the venting structure may restrict gas exchange from the pressurized volume (j) the exhaust gas flow path may include a region having a smaller cross-sectional area than an adjacent region of the exhaust gas flow path; (k) the exhaust gas flow path may include a restriction forming the region having the smaller cross-sectional area; (l) the membrane-facing surface may be closest to the movable portion of the membrane at the location of the restriction; (m) the membrane-facing surface may include a throttling portion forming the restriction in the exhaust gas flow path; (n) the membrane-facing surface may include a contour forming the throttling portion. (o) the restriction may include a surface; (o) the restriction may include a rib in the membrane-facing surface; (p) the restriction may include a region of increased material thickness; (q) the restriction may be centrally located between a first end of the membrane and a second end of the membrane; (r) the damping chamber may include a first end adjacent the first end of the membrane and a second end adjacent the second end of the membrane; (s) the restriction in the exhaust gas flow path may be centrally aligned between the first end of the damping chamber and the second end of the damping chamber; (t) the vent housing may be configured such that vibration of the movable portion of the membrane occurs primarily in a first vibration mode;(u) the damping chamber may be further defined by one or more walls of the second housing member; and / or (v) the damping chamber may be further defined by one or more walls of the membrane support;

[0097] In further example embodiments, (a) the ventilation gas flow may flow in a radial direction at or near the inlet to the exhaust gas flowpath; (b) the ventilation gas flow may turn from a radial direction to an axial direction aligned with the longitudinal axis of the vent structure at or near the inlet to the exhaust gas flowpath; (c) the vent housing may include a rounded surface at or near the inlet to the exhaust gas flowpath; and (d) the rounded surface may be configured to facilitate the ventilation gas flow turning at or near the inlet to the exhaust gas flowpath. (e) the vent housing may include a plurality of exhaust gas orifices; (f) the exhaust gas orifices may be spaced apart around the periphery of the vent housing; (g) the vent housing may include at least one diffused exhaust gas orifice and at least one non-diffused exhaust gas orifice; (h) the vent housing may include a plurality of diffused exhaust gas orifices and a plurality of non-diffused exhaust gas orifices; (i) at least one diffused exhaust gas orifice and at least one non-diffused exhaust gas orifice. (j) the diffusional exhaust gas orifices may be spaced apart along the longitudinal axis of the vent housing; (k) the non-diffusional exhaust gas orifice may be centrally located between the first end of the membrane and the second end of the vent housing; (l) the at least one diffusional exhaust gas orifice may open laterally; (m) the at least one non-diffusional exhaust gas orifice may open partially laterally and partially toward the second end of the vent housing; (n) the vent structure may include a diffuser member configured to diffuse and / or muffle gases in contact with the diffuser member during use; (o) the diffuser member may be arranged in series with the at least one diffusional exhaust gas orifice such that gases flowing through the at least one diffusional exhaust gas orifice are required to flow through the diffuser member; (p) the vent structure may provide a diffusional ventilation flow path. The diffusive ventilation flow path may allow ventilation of gases through the diffuser member and at least one diffusive exhaust gas orifice; (q) the ventilation structure may provide a non-diffusive ventilation flow path.The non-diffusional ventilation flow path may allow ventilation of gas through at least one non-diffusional exhaust gas orifice; (r) the ventilation structure may be configured to allow gas flow through the at least one non-diffusional exhaust gas orifice when the gas cannot pass through the at least one diffused exhaust gas orifice; (s) the ventilation structure may be shaped to require more redirection of the gas flow through the at least one non-diffusional exhaust gas orifice than through the diffused exhaust gas orifice; and / or (t) the ventilation structure may be shaped to require a redirection of the gas flow through the non-diffusional exhaust gas orifice to a sufficient extent that a majority of the exhaust gas flow passes through the diffuser member and the diffused exhaust gas aperture unless the diffuser member becomes clogged.

[0098] In further examples of the above embodiment, (a) the ventilation structure may include an exhaust gas orifice member including at least one exhaust gas orifice; (b) the exhaust gas orifice member may include a plurality of exhaust gas orifices; (c) the exhaust gas orifice member may be configured to connect to the first housing member; (d) the exhaust gas orifice member may be formed in a ring shape; (e) the exhaust gas orifice member may include a plurality of exhaust gas orifices spaced apart around a periphery of the ring; (f) at least (g) at least one diffusing exhaust gas orifice may be provided at or near a first end of the exhaust gas orifice member; (h) at least one non-diffusing exhaust gas orifice may be provided at or near a second end of the exhaust gas orifice member opposite the first end of the exhaust gas orifice member; (i) the diffuser member may be held within the ventilation structure by the exhaust gas orifice member; and / or (ii) the diffuser member may be housed between the exhaust gas orifice member and the first housing member.

[0099] In further examples of the above aspects, (a) the movable portion of the membrane may be positioned radially outward from the membrane-facing surface relative to the longitudinal axis of the membrane; (b) the movable portion of the membrane may be configured to move inward to restrict ventilation gas flow; (c) the movable portion of the membrane may be configured to contract and move inward toward the membrane-facing surface; (d) the membrane-facing surface may be provided on an outer surface of a first housing member disposed within the ventilation housing; (e) at least one protrusion may be provided outside the exhaust gas flow path; and (f) the ventilation housing may include a plurality of protrusions and a plurality of damping orifices defined between the plurality of protrusions. (g) the first housing member may include a shaft configured to protrude from a first end of the first housing member into an interior of the vent structure, the shaft having a membrane-facing surface on an outer surface of the shaft at or near a second end of the first housing member; (h) the shaft may be centrally disposed within the vent housing; (i) the shaft may be aligned with a longitudinal axis of the vent housing; (j) the rounded surface may be a fillet on the outer periphery of the first housing member at or near the entrance to the exhaust gas flow path; (k) the rounded surface may be provided on the shaft at the second end of the first housing member; (l) the vent housing may include a plurality of protrusions, and a plurality of damping orifices may be defined between the plurality of protrusions; (m) at least one protrusion may be provided on the second housing member; (n) the at least one protrusion may be disposed inwardly of the membrane; (o) the at least one protrusion may protrude into the first end of the vent housing; (p) the second housing member may include an inwardly extending membrane stop flange.(q) the at least one projection on the membrane stop flange may project axially into the first end of the vent housing; (r) the at least one projection may contact the inner surface of the membrane at the second end of the membrane; (r) the first housing member may include an outwardly projecting flange on the shaft at or near the first end of the first housing member; (s) the exhaust gas orifice member may be configured to connect to an outwardly extending flange on the first housing member opposite the second end of the first housing member; (t) the membrane support member may include a connector for connection to the vent housing; (u) the connector may be configured to connect directly or indirectly to the vent housing; (v) the connector may be cylindrically shaped and configured to fit around the outside of the second housing member; (w) the connector may be concentric with the membrane. (x) the membrane support may include a membrane support flange formed as a flange extending inward from the interior of the connection portion of the membrane support; (y) the membrane may be molded to the membrane support flange; (z) the membrane support flange may be spaced apart from the end of the connection portion; (aa) the exhaust gas orifice member and the membrane support may be configured to be connected together to connect the first housing member and the second housing member; (ab) the connection portion of the membrane support may be configured to connect to the exhaust gas orifice member; (ac) the connection portion of the membrane support may be configured to form a press fit with the exterior of the exhaust gas orifice member; and / or (ad) when the membrane support is connected to both the exhaust gas orifice member and the second housing member, the membrane support flange may be disposed between the exhaust gas orifice member and the second housing member.

[0100] In further examples of the above embodiment, (a) the movable portion of the membrane may be supported radially inward from the membrane-facing surface relative to the longitudinal axis of the membrane; (b) the movable portion of the membrane may be configured to move outward to restrict vent gas flow; (c) the movable portion of the membrane may be configured to expand and move outward toward the membrane-facing surface; (d) the membrane-facing surface may be provided on an inner surface of the first housing member; (e) the membrane-facing surface may be cylindrical or frustoconical; (f) the membrane support portion may include a baffle portion; (g) the baffle portion may be cylindrical; (h) the baffle portion may be in contact with the movable portion of the membrane. (i) the baffle portion may be disposed within the movable portion of the membrane; (j) the baffle portion may have a first end connected to the movable portion of the membrane at the first end of the membrane and a second end disposed at or adjacent the second end of the membrane; (k) the baffle portion may include an outwardly extending flange at the second end of the baffle portion; (l) the rounded surface may be a fillet disposed on the second end support of the membrane at or adjacent the entrance to the exhaust gas flow path; (m) the rounded surface may be disposed on the outwardly extending flange of the baffle portion of the membrane support; (n) the damping chamber is (o) the damping chamber may be defined in part by a baffle portion of the membrane support; (o) the damping chamber may be defined in part by an outwardly extending flange of the baffle portion; (p) the at least one protrusion may be provided on the first housing member; (q) the at least one protrusion may protrude radially inward from the cylindrical or conical surface of the first housing member; (r) the at least one protrusion may contact an outer surface of the membrane at the second end of the membrane; (s) the first housing member may include at least one intermediate exhaust gas orifice upstream of the diffuser member; (t) the diffuser member may include at least one intermediate exhaust gas orifice upstream of the diffuser member; (u) the second housing member may include a diffuser retainer; (v) the diffuser retainer may include a cylindrical sleeve configured to fit over the first housing member; (w) the first housing member may be substantially cylindrical, the second housing member connection portion being provided at the second end of the first housing member, and the diffuser support flange being provided at the second end of the first housing member;(x) a diffuser may be retained in the diffuser flow passage between the diffuser support flange of the first housing member, the second housing member connecting portion of the first housing member, and the diffuser retainer of the second housing member; (y) at least one exhaust gas orifice may be provided in the diffuser retainer of the second housing member or may be formed by a gap between the diffuser retainer of the second housing member and the diffuser support flange of the first housing member; and / or (z) a plurality of exhaust gas orifices may be provided in the diffuser retainer of the second housing member and / or in a gap between the diffuser retainer of the second housing member and the diffuser support flange of the first housing member;

[0101] 3.3 Ventilated structure with damping structure to attenuate membrane vibration Another aspect of the present technology relates to a ventilation system for use with a patient interface to provide respiratory therapy to a patient using a therapeutic gas flow pressurized above atmospheric pressure within a therapeutic pressure range. The therapeutic gas flow may be pressurized by a respiratory pressure therapy device and may be provided throughout the patient's respiratory cycle. The ventilation system may be configured to provide a ventilation gas flow from a pressurized volume for releasing exhaled gases by the patient. The ventilation gas flow may be continuous throughout the patient's respiratory cycle. The ventilation system may include a ventilation housing. The vent housing includes at least one exhaust gas orifice configured to allow exhaust gas to escape from the pressurized volume to the atmosphere; a membrane disposed within the vent housing, the membrane having a movable portion spaced apart from an inner membrane-facing surface of the vent housing to form an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface, the exhaust gas flow path configured to allow exhaust gas to flow from the pressurized volume to the atmosphere through the at least one exhaust gas orifice; and a damping structure configured to damp vibrations of the movable portion of the membrane, the damping structure including a damping chamber within the vent housing. The movable portion of the membrane may be elastically deformable and configured to move relative to the membrane-facing surface in response to a pressure differential between a first side of the membrane and a second side of the membrane to allow for a change in the cross-sectional area of ​​the exhaust gas flow path and adjustment of ventilation gas flow throughout the treatment pressure range. The first side of the movable portion of the membrane may face the membrane-facing surface, and the second side of the movable portion of the membrane may partially define the damping chamber.

[0102] 1. A patient interface comprising: a plenum chamber at least partially defining a volume which, in use, is pressurizable to a therapeutic pressure of at least 6 cmH2O above ambient air pressure throughout the patient's respiratory cycle, said plenum chamber including a plenum chamber inlet port sized and configured to receive a therapeutic gas flow for breathing by the patient; a seal-forming structure constructed and arranged to seal against an area of ​​the patient's face surrounding an entrance to the patient's airways, said seal-forming structure having holes therein whereby said therapeutic gas flow is delivered to at least entrances to the patient's nares in use, said seal-forming structure constructed and arranged to maintain said therapeutic pressure within the plenum chamber throughout the patient's respiratory cycle; a positioning and stabilizing structure configured to hold said seal-forming structure in a therapeutically effective position on the patient's head; and a venting structure for venting the ventilated gas flow to atmosphere throughout the patient's respiratory cycle.The venting structure includes a venting housing including at least one exhaust gas orifice for gas release to atmosphere, the at least one exhaust gas orifice being sized and shaped to maintain a therapeutic pressure in the plenum chamber in use; a membrane disposed within the venting housing, the membrane having a movable portion spaced apart from a membrane-facing surface inside the venting housing to form an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface, the exhaust gas flow path being configured to allow exhaust gas flow from the pressurized volume to atmosphere through the at least one exhaust gas orifice; and a damping structure configured to damp vibrations of the movable portion of the membrane, the damping structure connecting the damping chamber to the venting housing. 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.

[0103] In examples of the above embodiments, (a) the vent housing may partially define a damping chamber; (b) the damping chamber may be in fluid communication with the pressurized volume in use; (c) the vent structure may be configured such that the volume of the damping chamber increases or decreases due to movement of the movable portion of the membrane; (d) the vent housing and the damping chamber may be configured to damp vibrations of the movable portion of the membrane by restricting gas exchange between the damping chamber and the pressurized volume; and (e) the vent structure may include at least one damping orifice through which gas may flow to the pressurized volume. (f) the vent structure may include a plurality of damping orifices through which gas from the pressurized volume can flow into and out of the damping chamber, the plurality of damping orifices together supporting gas exchange between the damping chamber and the pressurized volume; (g) the damping chamber may have a first end adjacent to the first end of the membrane and a second end adjacent to the second end of the membrane. (h) the exhaust gas flow path may include a region having a smaller cross-sectional area than an adjacent region of the exhaust gas flow path; (i) the exhaust gas flow path may include a restriction forming the region having the smaller cross-sectional area; (j) the membrane-facing surface may be closest to the movable portion of the membrane at the location of the restriction; (k) the restriction in the exhaust gas flow path may be centrally aligned between the first end of the damping chamber and the second end of the damping chamber; (l) the membrane-facing surface may include a throttling portion forming the restriction in the exhaust gas flow path; (m) the membrane-facing surface may include a contoured surface forming the throttling portion. (n) the restriction may include a rib in the membrane-facing surface; (o) the restriction may include a region of increased material thickness; (p) the restriction may be centrally located between a first end of the membrane and a second end of the membrane; (q) the damping chamber may include a first end adjacent the first end of the membrane and a second end adjacent the second end of the membrane, and the restriction in the exhaust gas flow path is centrally located between the first end of the damping chamber and the second end of the damping chamber; (r) the vent housing may be configured to reduce vibration of the movable portion of the membrane at vibration modes higher than a primary vibration mode;(s) the vent housing may include an inlet device for receiving gas flow from the respiratory pressure therapy device and an outlet for supplying the therapeutic gas flow to the patient interface; (t) the vent housing may include a first housing member at a first end of the vent housing and a second housing member at a second end of the vent housing, the first housing member and the second housing member being configured to be connected together; (u) the first housing member may include an inlet and an inlet connection configured to fluidly connect the vent structure to a supply conduit; and / or (v) the second housing member may include an outlet and an outlet connection configured to fluidly connect the vent structure to the patient interface; and / or (w) the exhaust gas flow path may occupy a continuous space all around within the vent housing;

[0104] 3.4 Vented housing to dampen membrane vibrations in modes higher than the first mode Another aspect of the present technology relates to a ventilation system for use with a patient interface to provide respiratory therapy to a patient using a therapeutic gas flow pressurized above atmospheric pressure within a therapeutic pressure range. The therapeutic gas flow may be pressurized by a respiratory pressure therapy device and provided throughout the patient's respiratory cycle. The ventilation system may be configured to provide a ventilation gas flow from a pressurized volume for releasing exhaled gases from the patient. The ventilation gas flow may be continuous throughout the patient's respiratory cycle. The ventilation system may include a ventilation housing including at least one exhaust gas orifice configured to allow exhaust gas to be released from the pressurized volume to atmosphere; and a membrane within the ventilation housing, the membrane having a movable portion. The movable portion of the membrane may be spaced from an inner membrane-facing surface of the ventilation housing to form an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface, the exhaust gas flow path being configured to allow exhaust gas from the pressurized volume to flow through the exhaust gas flow path and the at least one exhaust gas orifice to atmosphere. The movable portion of the membrane can be elastically deformable and can be configured to move relative to the membrane-facing surface in response to a pressure differential between the first side of the membrane and the second side of the membrane to allow for variation in cross-sectional area of ​​the exhaust gas flow path and adjustment of ventilation gas flow throughout a treatment pressure range. The vent housing can be configured to reduce vibration of the movable portion of the membrane in modes higher than a first vibration mode.

[0105] In accordance with another aspect of the present technology, there is provided a patient interface comprising: a plenum chamber at least partially defining a pressurized volume of the patient interface that is pressurizable in use to a therapeutic pressure of at least 6 cmH2O above ambient air pressure throughout a patient's respiratory cycle, said plenum chamber including a plenum chamber inlet port sized and configured to receive a therapeutic gas flow from the pressurized volume for breathing of the patient; and 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 having holes therein. a seal-forming structure whereby a therapeutic gas flow is delivered to an entrance to at least the patient's nares, the seal-forming structure constructed and arranged to maintain said therapeutic pressure in a plenum chamber in use throughout the patient's respiratory cycle; a positioning and stabilizing structure which provides a force to hold said seal-forming structure in a therapeutically effective position on the patient's head; and a venting structure which allows a continuous flow of vent gas throughout the patient's respiratory cycle to vent exhaust gases exhaled by the patient from a pressurized volume to the environment, said venting structure being sized and shaped to maintain said therapeutic pressure in the plenum chamber in use.The vent structure includes: a vent housing including at least one exhaust gas orifice that allows exhaust gas from the pressurized volume to be released to the atmosphere; a membrane within the vent housing, the membrane having a movable portion; the movable portion of the membrane spaced apart from an interior membrane-facing surface of the vent housing to define an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface, the exhaust gas flow path allowing exhaust gas from the pressurized volume to flow through the exhaust gas flow path and through the at least one exhaust gas orifice to the atmosphere in use; the movable portion of the membrane being elastically deformable and configured to be in contact with a first side of the membrane and a second side of the membrane. the patient interface is configured to move relative to the membrane facing surface in response to a pressure differential between the two sides thereof to vary the cross-sectional area of ​​the exhaust gas flow path and regulate the ventilation gas flow throughout a treatment pressure range, the ventilation housing being configured to reduce vibration of the movable portion of the membrane in vibration modes higher than a first vibration mode; and 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.

[0106] In examples of the above embodiment, (a) the vent structure may include a damping structure configured to damp vibrations of the movable portion of the membrane; (b) the damping structure may include a damping chamber within the vent housing; (c) the vent housing may partially define the damping chamber; (d) a first side of the movable portion of the membrane may face the membrane-facing surface, and a second side of the movable portion of the membrane may partially define the damping chamber; (e) the damping chamber may be in fluid communication with a pressurized volume in use; and (f) the vent structure may be configured such that movement of the movable portion of the membrane increases or decreases the volume of the damping chamber. (g) the venting housing and the damping chamber may be configured to damp vibrations of the moving part of the membrane by restricting gas exchange between the damping chamber and the pressurized volume; (h) the venting structure may include at least one damping orifice through which gas from the pressurized volume can flow into and out of the damping chamber, the damping orifice resisting gas exchange between the damping chamber and the pressurized volume; (i) the venting structure may provide a passageway for gas from the pressurized volume to flow into and out of the damping chamber. (j) the damping chamber may include a first end adjacent the first end of the membrane and a second end adjacent the second end of the membrane; (k) the exhaust gas flow path may include a region having a smaller cross-sectional area than an adjacent region of the exhaust gas flow path; (l) the exhaust gas flow path may include a restriction forming a region having a smaller cross-sectional area; (m) the membrane-facing surface may be closest to the movable portion of the membrane at the location of the restriction; (n) the membrane-facing surface may include a throttling portion forming a restriction in the exhaust gas flow path. (o) the membrane-facing surface may include a contoured surface forming a restriction; (p) the restriction may include a rib in the membrane-facing surface; (q) the restriction may include an area of ​​increased material thickness; (r) the restriction may be centrally located between a first end of the membrane and a second end of the membrane; (s) the restriction in the exhaust gas flow path may be centrally aligned between a first end of the damping chamber and a second end of the damping chamber; (t) the vent housing may include an inlet device for receiving gas flow from the respiratory pressure therapy device and an outlet for delivering therapeutic gas flow to the patient interface;(u) the vent housing may include a first housing member at a first end of the vent housing and a second housing member at a second end of the vent housing, the first housing member and the second housing member being configured to be connected together; (v) the first housing member may include an inlet and an inlet connection configured to fluidly connect the vent structure to a supply conduit; (w) the second housing member may include an outlet and an outlet connection configured to fluidly connect the vent structure to a patient interface; (x) the exhaust gas flow path may occupy a continuous space around the entire circumference within the vent housing;

[0107] 3.5 Vented housing with stagnant air cavity Another aspect of the present technology relates to a ventilation system for use with a patient interface to provide respiratory therapy to a patient using a therapeutic gas flow pressurized above atmospheric pressure within a therapeutic pressure range. The therapeutic gas flow may be pressurized by a respiratory pressure therapy device and may be provided throughout the patient's respiratory cycle. The ventilation system is configured to provide a ventilation gas flow from a pressurized volume for releasing the patient's exhaled gases. The ventilation gas flow may be continuous throughout the patient's respiratory cycle. The ventilation system may include: a ventilation housing including at least one exhaust gas orifice that allows exhaust gas from the pressurized volume to be released to atmosphere; a membrane within the ventilation housing, the membrane having a movable portion with a first side and a second side; and a stagnant air cavity within the ventilation housing on the first side of the movable portion of the membrane, the movable portion of the membrane at least partially defining the stagnant air cavity. The movable portion of the membrane can be spaced from the membrane-facing surface inside the vent housing to form an exhaust gas flow path on the second side of the membrane between the movable portion of the membrane and the membrane-facing surface, the exhaust gas flow path allowing exhaust gas from the pressurized volume to flow through the exhaust gas flow path and through the at least one exhaust gas orifice to the atmosphere. The movable portion of the membrane can be elastically deformable and configured to move relative to the membrane-facing surface in response to a pressure differential between the first side of the membrane and the second side of the membrane to allow changing the cross-sectional area of ​​the exhaust gas flow path and regulating vent gas flow throughout the treatment pressure range.

[0108] According to another aspect of the present technology, there is provided a patient interface comprising: a plenum chamber at least partially defining a volume that is pressurizable in use to a therapeutic pressure of at least 6 cmH2O above ambient air pressure throughout a patient's respiratory cycle, said plenum chamber including a plenum chamber inlet port sized and configured to receive a therapeutic gas flow for breathing of the patient; a seal-forming structure constructed and arranged to seal against an area of ​​the patient's face surrounding an entrance to the patient's airways, said seal-forming structure having holes therein whereby said therapeutic gas flow is delivered to at least entrances to the patient's nares in use, the seal-forming structure constructed and arranged to maintain said therapeutic pressure within the plenum chamber throughout the patient's respiratory cycle; a positioning and stabilizing structure configured to hold said seal-forming structure in a therapeutically effective position on the patient's head; and a venting structure configured to exhaust the venting gas flow to atmosphere throughout the patient's respiratory cycle.The vent structure includes: a vent housing including at least one exhaust gas orifice for gas release to the atmosphere, the at least one exhaust gas orifice sized and shaped to maintain a therapeutic pressure in the plenum chamber in use; a membrane disposed within the vent housing, the membrane having a movable portion having a first side and a second side; a stagnant air cavity disposed within the vent housing on a first side of the movable portion of the membrane, the movable portion of the membrane at least partially defining the stagnant air cavity; the movable portion of the membrane spaced apart from a membrane-facing surface on the interior of the vent housing to provide an exhaust gas flow path through a second portion of the membrane between the movable portion of the membrane and the membrane-facing surface. a patient interface 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, to leave the patient's oral cavity exposed.

[0109] In examples of the above embodiment, (a) the vent housing may partially define a stagnant air cavity; (b) the stagnant air cavity may include a damping chamber configured to damp vibrations of the movable portion of the membrane; (c) the vent housing may partially define the damping chamber; (d) one of the first side and the movable portion of the second side of the membrane may face the membrane-facing surface, and the other of the first side and the movable portion of the second side of the membrane may partially define the damping chamber; (e) the damping chamber may be in fluid communication with the pressurized volume in use; and (f) the vent housing may partially define the damping chamber; The structure may be configured such that movement of the movable portion of the membrane increases or decreases the volume of the damping chamber; (g) the vent housing and the damping chamber may be configured to damp vibration of the movable portion of the membrane by restricting gas exchange between the damping chamber and the pressurized volume; (h) the vent structure may include at least one damping orifice through which gas from the pressurized volume can flow into and out of the damping chamber, the damping orifice supporting gas exchange between the damping chamber and the pressurized volume; (i) the vent structure may include a plurality of damping orifices through which gas from the pressurized volume can flow into and out of the damping chamber, the plurality of damping orifices together supporting gas exchange between the damping chamber and the pressurized volume; (j) the damping chamber may include a first end adjacent to the first end of the membrane and a second end adjacent to the second end of the membrane; (k) the exhaust gas flow path may include a region having a smaller cross-sectional area than an adjacent region of the exhaust gas flow path; (l) the exhaust gas flow path may include a restriction forming a region having a smaller cross-sectional area. (m) the membrane-facing surface may be closest to the movable portion of the membrane at the location of the restriction; (n) the membrane-facing surface may include a constriction that forms a restriction in the exhaust gas flow path; (o) the membrane-facing surface may include a contoured surface that forms the constriction; (p) the constriction may include a rib in the membrane-facing surface; (q) the constriction may include a region of increased material thickness; (e) the constriction may be centrally located between the first end of the membrane and the second end of the membrane; (s) the restriction in the exhaust gas flow path may be centrally aligned between the first end of the damping chamber and the second end of the damping chamber;(t) the vent housing may include an inlet device for receiving gas flow from the respiratory pressure therapy device and an outlet for supplying the therapeutic gas flow to the patient interface; (u) the vent housing may include a first housing member at a first end of the vent housing and a second housing member at a second end of the vent housing, the first housing member and the second housing member being configured to be connected together; (v) the first housing member may include an inlet and an inlet connection configured to fluidly connect the vent structure to a supply conduit; (w) the second housing member may include an outlet and an outlet connection configured to fluidly connect the vent structure to the patient interface; (x) the vent housing may be configured such that vibration of the movable portion of the membrane occurs primarily in a first vibration mode; and / or (y) the exhaust gas flow path may occupy a continuous space around the entire circumference within the vent housing;

[0110] In further examples of the above embodiment: (a) a first side of the movable portion of the membrane faces radially inward and a movable portion of the second side of the membrane faces radially outward; (b) a first side of the movable portion of the membrane faces radially outward and a movable portion of the second side of the membrane faces radially inward; and / or (c) the membrane has a first end and a second end spaced apart along a longitudinal axis of the membrane, and the movable portion is disposed between the first end of the membrane and the second end of the membrane surrounding the longitudinal axis.

[0111] 3.6 Exhaust gas flow path containing areas of smaller cross-sectional area than adjacent areas Another aspect of the present technology relates to a ventilation system for use with a patient interface to provide respiratory therapy to a patient using a therapeutic gas flow pressurized above atmospheric pressure within a therapeutic pressure range. The therapeutic gas flow may be pressurized by a respiratory pressure therapy device and may be provided throughout the patient's respiratory cycle. The ventilation system may be configured to provide a ventilation gas flow from a pressurized volume for venting the patient's exhaled gases, the ventilation system including: a vent housing including at least one exhaust gas orifice that allows exhaust gases from the pressurized volume to be vented to atmosphere; a membrane within the vent housing, the membrane having a movable portion having a first side and a second side, the movable portion of the membrane spaced from a membrane-facing surface inside the vent housing to define an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface; a membrane formed on the side and having an exhaust gas flow path that, in use, allows exhaust gas from the pressurized volume to flow through the exhaust gas flow path and through at least one exhaust gas orifice to the atmosphere; the exhaust gas flow path includes an area having a smaller cross-sectional area than an adjacent area of ​​the exhaust gas flow path, and a movable portion of the membrane is elastically deformable and configured to move relative to the membrane-facing surface in response to a pressure differential between a first side of the membrane and a second side of the membrane to allow variation of the cross-sectional area of ​​the exhaust gas flow path and adjustment of ventilation gas flow throughout a treatment pressure range.

[0112] 1. A patient interface comprising: a plenum chamber at least partially defining a volume that is pressurizable in use to a therapeutic pressure of at least 6 cmH2O above ambient air pressure throughout a patient's respiratory cycle, said plenum chamber including a plenum chamber inlet port sized and configured to receive a therapeutic gas flow from the volume for breathing of the patient; a seal-forming structure constructed and arranged to seal against an area of ​​the patient's face surrounding an entrance to the patient's airways, said seal-forming structure having holes therein whereby said therapeutic gas flow is delivered to at least entrances to the patient's nares in use, said seal-forming structure constructed and arranged to maintain said therapeutic pressure within the plenum chamber throughout the patient's respiratory cycle; a positioning and stabilizing structure configured to hold said seal-forming structure in a therapeutically effective position on the patient's head; and a venting structure configured to exhaust the venting gas flow to atmosphere throughout the patient's respiratory cycle.The vent structure includes: a vent housing including at least one exhaust gas orifice configured to release gas to the atmosphere, the at least one exhaust gas orifice sized and shaped to maintain a therapeutic pressure in the plenum chamber in use; and a membrane disposed within the vent housing, the membrane having a first end and a second end spaced apart along a longitudinal axis of the membrane, the membrane having a movable portion disposed between the first end and the second end of the membrane and surrounding the longitudinal axis, the movable portion of the membrane including a first side and a second side and spaced apart radially from a membrane-facing surface on an interior side of the vent housing about the longitudinal axis of the membrane to form an exhaust gas flow path on the second side of the membrane between the movable portion of the membrane and the membrane-facing surface, the exhaust gas flow path being such that, in use, the exhaust gas flow path includes a region between a movable portion of the membrane and a membrane-facing surface having a cross-sectional area smaller than an adjacent region of the exhaust gas flow path, the movable portion of the membrane being elastically deformable and configured to move radially relative to the membrane-facing surface in response to a pressure differential between a first side of the membrane and a second side of the membrane to allow variation of the cross-sectional area of ​​the exhaust gas flow path and adjustment of ventilation gas flow throughout a treatment pressure range; 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.

[0113] In examples of the above embodiments, (a) the exhaust gas flow path may include a restriction forming an area having a smaller cross-sectional area; (b) the membrane-facing surface may be closest to the movable portion of the membrane at the location of the restriction; (c) the membrane-facing surface may include a throttling portion forming the restriction in the exhaust gas flow path; (d) the membrane-facing surface may include a contoured surface forming the throttling portion; (e) the throttling portion may include a rib in the membrane-facing surface; (f) the throttling portion may be centrally disposed between a first end of the membrane and a second end of the membrane; (g) the vent structure may include a damping chamber in the vent housing configured to damp vibrations of the movable portion of the membrane, the damping chamber may include a first end proximate the first end of the membrane and a second end proximate the second end of the membrane, and the restriction in the exhaust gas flow path is centrally aligned between the first end of the damping chamber and the second end of the damping chamber; (h) The vent housing may include an inlet device for receiving the gas flow from the respiratory pressure therapy device and an outlet for supplying the therapeutic gas flow to the patient interface; (i) the vent housing may include a first housing member at a first end of the vent housing and a second housing member at a second end of the vent housing, the first housing member and the second housing member being configured to be connected together; (j) the first housing member may include an inlet and an inlet connection configured to fluidly connect the vent structure to a supply conduit; (k) the second housing member may include an outlet and an outlet connection configured to fluidly connect the vent structure to the patient interface; and / or (l) the exhaust gas flow path may occupy a continuous space around the entire circumference within the vent housing.

[0114] 3.7 Ventilated structure with a membrane that deforms radially outward Another aspect of the present technology relates to a ventilation system for use with a patient interface to provide respiratory therapy to a patient using a therapeutic gas flow pressurized above atmospheric pressure within a therapeutic pressure range. The therapeutic gas flow may be pressurized by a respiratory pressure therapy device and may be provided throughout the patient's respiratory cycle. The ventilation system may be configured to provide a ventilation gas flow from the pressurized volume for releasing exhaled gases by the patient. The ventilation gas flow may be continuous throughout the patient's respiratory cycle. The ventilation system may include: a ventilation housing including at least one exhaust gas orifice that allows exhaust gases from the pressurized volume to be released to atmosphere; and a membrane within the ventilation housing, the membrane having first and second ends spaced apart along a longitudinal axis of the membrane, the membrane having a movable portion between the first and second ends that surround the longitudinal axis. The movable portion of the membrane may be spaced radially inward relative to the longitudinal axis of the membrane from the inner membrane-facing surface of the vent housing to define an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface, which, in use, allows exhaust gas from the pressurized volume to flow through the exhaust gas flow path and through the at least one exhaust gas orifice to the atmosphere. The movable portion of the membrane is elastically deformable and configured to move radially relative to the membrane-facing surface in response to a pressure differential between the inside and outside of the membrane, thereby varying the cross-sectional area of ​​the exhaust gas flow path and regulating vent gas flow throughout a therapeutic pressure range.

[0115] According to another aspect of the present technology, there is provided a patient interface comprising: a plenum chamber at least partially defining a volume that is pressurizable in use to a therapeutic pressure of at least 6 cmH2O above ambient air pressure throughout a patient's respiratory cycle, said plenum chamber including a plenum chamber inlet port sized and configured to receive a therapeutic gas flow from the pressurized volume for breathing of the patient; a seal-forming structure constructed and arranged to seal against an area of ​​the patient's face surrounding an entrance to the patient's airways, said seal-forming structure having holes therein whereby said therapeutic gas flow is delivered to at least entrances to the patient's nares in use, said seal-forming structure constructed and arranged to maintain said therapeutic pressure within the plenum chamber throughout the patient's respiratory cycle; a positioning and stabilizing structure configured to hold said seal-forming structure in a therapeutically effective position on the patient's head; and a venting structure configured to exhaust the venting gas flow to atmosphere throughout the patient's respiratory cycle.The vent structure includes: a vent housing including at least one exhaust gas orifice configured to release gas to the atmosphere, the at least one exhaust gas orifice being sized and shaped to maintain a therapeutic pressure in the plenum chamber in use; and a membrane disposed within the vent housing, the membrane having a first end and a second end spaced apart along a longitudinal axis of the membrane, the membrane having a movable portion disposed between the first end and the second end of the membrane and surrounding the longitudinal axis, the movable portion of the membrane being spaced radially inward relative to the longitudinal axis of the membrane from a membrane-facing surface on the inside of the vent housing to define an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface. the exhaust gas flow path is configured to, in use, allow exhaust gas from the pressurized volume to flow through the exhaust gas flow path and through the at least one exhaust gas orifice to atmosphere; the movable portion of the membrane is elastically deformable and configured to move radially relative to the membrane facing surface in response to a pressure differential between an inside of the membrane and an outside of the membrane to thereby vary a cross-sectional area of ​​the exhaust gas flow path and regulate ventilation gas flow throughout a treatment pressure range; and 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.

[0116] In examples of the above embodiment, (a) the movable portion of the membrane may be substantially cylindrical or frustoconical; (b) the vent housing may include a first end and a second end aligned along a longitudinal axis of the vent housing, the longitudinal axis of the membrane being aligned with the longitudinal axis of the vent housing; (c) the longitudinal axis of the membrane may be aligned substantially parallel to the direction of gas flow through the vent housing from the first end of the vent housing to the second end of the vent housing; (d) the movable portion of the membrane may be aligned substantially parallel to the direction of gas flow through the vent housing from the first end of the vent housing to the second end of the vent housing; (e) the movable portion of the membrane may include one or more wall portions aligned parallel to the direction of gas flow through the vent housing from the first end of the vent housing to the second end of the vent housing; (f) the vent structure may include a membrane support portion supporting the membrane; (g) the membrane may be molded to the membrane support portion at the first end of the membrane; (h) the membrane support portion may be configured to connect to the vent housing; (i) the movable portion of the membrane may be made of silicone rubber (j) the vent housing may include a first housing member at a first end of the vent housing and a second housing member at a second end of the vent housing, the first housing member and the second housing member being configured to be connected together; (k) the first housing member may include an inlet connection configured to fluidly connect the vent structure to a supply conduit; (l) the inlet connection may be provided at or near the first end of the first housing portion; (m) the inlet connection engages with a corresponding fitting on the supply conduit. (n) the second housing member may include an outlet connection configured to fluidly connect the vent structure to a patient interface; (o) the outlet connection may be configured to connect to a patient interface or tubing connected to the patient interface; (p) the outlet connection may include internal threads configured to engage with corresponding threads on the patient interface or patient interface tubing; and / or (q) the exhaust gas flow path may occupy a continuous space all around within the vent housing.

[0117] In further example embodiments, (a) the vent structure may include a damping structure configured to damp vibrations of the movable portion of the membrane; (b) the damping structure may include a damping chamber within the vent housing; (c) the vent housing may partially define the damping chamber; (d) one of the inner and outer sides of the membrane may face the membrane-facing surface, and the other of the inner and outer sides of the membrane may partially define the damping chamber; (e) the damping chamber may be in fluid communication with a pressurized volume in use; and (f) the vent structure may be configured such that movement of the movable portion of the membrane increases or decreases the volume of the damping chamber. (g) the venting housing and the damping chamber may be configured to damp vibrations of the movable part of the membrane by restricting gas exchange between the damping chamber and the pressurized volume; (h) the venting structure may include at least one damping orifice through which gas from the pressurized volume can flow into and out of the damping chamber, the damping orifice resisting gas exchange between the damping chamber and the pressurized volume; (i) the venting structure may restrict gas from the pressurized volume to flow into and out of the damping chamber; (j) the exhaust gas flow path may include a region having a smaller cross-sectional area than adjacent regions of the exhaust gas flow path; (k) the exhaust gas flow path may include a restriction forming a region having a smaller cross-sectional area; (l) the membrane-facing surface may be closest to the movable portion of the membrane at the location of the restriction; (m) the membrane-facing surface may include a throttling portion forming a restriction in the exhaust gas flow path; (n) the membrane-facing surface may include a contoured surface forming the throttling portion; (o) the restriction may include a rib in the membrane-facing surface; (p) the restriction may include a region of increased material thickness; (q) the restriction may be centrally located between a first end of the membrane and a second end of the membrane; (r) the damping chamber may include a first end adjacent the first end of the membrane and a second end adjacent the second end of the membrane; (s) the restriction in the exhaust gas flow path may be centrally aligned between the first end of the damping chamber and the second end of the damping chamber; (t) the vent housing may be configured such that vibration of the movable portion of the membrane occurs primarily in a first vibration mode;(u) the damping chamber may be further defined by one or more walls of the second housing member; and / or (v) the damping chamber may be further defined by one or more walls of the membrane support;

[0118] In further examples of the above aspects, (a) the ventilation housing may be configured to restrict movement of the movable portion of the membrane toward the membrane-facing surface; (b) the ventilation housing may contact the edge of the membrane and prevent the edge of the membrane from moving toward the membrane-facing surface; (c) the ventilation housing may include at least one protrusion, which is configured to contact the edge of the membrane and restrict movement of the edge of the membrane toward the membrane-facing surface; (d) the at least one protrusion is provided outside the exhaust gas flow path; and / or (e) the ventilation housing may include a plurality of protrusions, and a plurality of damping orifices may be defined between the plurality of protrusions, through which gas can flow from the pressurized volume into and out of the damping chamber, and the damping orifices resist gas exchange between the damping chamber and the pressurized volume to damp vibration of the movable portion of the membrane.

[0119] In further example embodiments, (a) the ventilation gas flow may flow in a radial direction at or near the inlet to the exhaust gas flowpath; (b) the ventilation gas flow may turn from a radial direction to an axial direction aligned with a longitudinal axis of the ventilation structure as it passes through the inlet to the exhaust gas flowpath; (c) the ventilation housing may include a rounded surface at or near the inlet to the exhaust gas flowpath; (d) the rounded surface may facilitate turning of the ventilation gas flow near the inlet to the exhaust gas flowpath; (e) the ventilation housing may include a plurality of exhaust gas orifices; (f) the exhaust gas orifices may (g) the vent housing may include at least one diffused exhaust gas orifice and at least one non-diffused exhaust gas orifice; (h) the vent housing may include a plurality of diffused exhaust gas orifices and a plurality of non-diffused exhaust gas orifices; (i) the at least one diffused exhaust gas orifice and the at least one non-diffused exhaust gas orifice may be spaced apart along a longitudinal axis of the vent housing; (j) the diffused exhaust gas orifice is located at a first position on the vent housing. (k) the non-diffused exhaust gas orifice may be centrally located between the first end of the vent housing and the second end of the vent housing; (l) the at least one diffused exhaust gas orifice may open in a lateral direction; (m) the at least one non-diffused exhaust gas orifice may open partially toward the second end of the vent housing in a direction oblique to the lateral direction; (n) the vent structure may include a diffuser member configured to diffuse and / or muffle exhaust gases; (o) the diffuser member may include at least one (p) the ventilation structure may provide a diffusive ventilation flow path that allows exhaust gases to vent through the diffuser member and the at least one diffusive exhaust gas orifice; (q) the ventilation structure may provide a non-diffusive ventilation flow path that allows exhaust gases to vent through the at least one non-diffusive exhaust gas orifice;(r) the ventilation structure may be configured to allow exhaust gas flow through the at least one non-diffusion type exhaust gas orifice when the exhaust gas cannot rise through the at least one diffusion type exhaust gas orifice; (s) the ventilation structure may be shaped to require more exhaust gas flow redirection through the at least one non-diffusion type exhaust gas orifice than through the diffusion type exhaust gas orifice; and / or (t) the ventilation structure may be shaped to require exhaust gas flow redirection through the non-diffusion type exhaust gas orifice to a sufficient extent that a majority of the exhaust gas flow passes through the diffuser member and the diffusion type exhaust gas aperture unless the diffuser member becomes clogged;

[0120] In further examples of the above embodiment, (a) the ventilation structure may include an exhaust gas orifice member including at least one exhaust gas orifice; (b) the exhaust gas orifice member may include a plurality of exhaust gas orifices; (c) the exhaust gas orifice member may be configured to connect to the first housing member; (d) the exhaust gas orifice member may be formed in a ring shape; (e) the exhaust gas orifice member may include a plurality of exhaust gas orifices spaced apart around a periphery of the ring; (f) at least (g) at least one diffusing exhaust gas orifice may be provided at or near a first end of the exhaust gas orifice member; (h) at least one non-diffusing exhaust gas orifice may be provided at or near a second end of the exhaust gas orifice member opposite the first end of the exhaust gas orifice member; (i) the diffuser member may be held within the ventilation structure by the exhaust gas orifice member; and / or (ii) the diffuser member may be housed between the exhaust gas orifice member and the first housing member.

[0121] In further examples of the above embodiment, (a) the movable portion of the membrane may be supported radially inward from the membrane-facing surface relative to the longitudinal axis of the membrane; (b) the movable portion of the membrane may be configured to move outward to restrict vent gas flow; (c) the movable portion of the membrane may be configured to expand and move outward toward the membrane-facing surface; (d) the membrane-facing surface may be provided on an inner surface of the first housing member; (e) the membrane-facing surface may be cylindrical or frustoconical; (f) the membrane support portion may include a baffle portion; (g) the baffle portion may be cylindrical; (h) the baffle portion may be in contact with the movable portion of the membrane. (i) the baffle portion may be disposed within the movable portion of the membrane; (j) the baffle portion may have a first end connected to the movable portion of the membrane at the first end of the membrane and a second end disposed at or adjacent the second end of the membrane; (k) the baffle portion may include an outwardly extending flange at the second end of the baffle portion; (l) the rounded surface may be a fillet disposed on the second end support of the membrane at or adjacent the entrance to the exhaust gas flow path; (m) the rounded surface may be disposed on the outwardly extending flange of the baffle portion of the membrane support; (n) the damping chamber is (o) the damping chamber may be defined in part by a baffle portion of the membrane support; (o) the damping chamber may be defined in part by an outwardly extending flange of the baffle portion; (p) the at least one protrusion may be provided on the first housing member; (q) the at least one protrusion may protrude radially inward from the cylindrical or conical surface of the first housing member; (r) the at least one protrusion may contact an outer surface of the membrane at the second end of the membrane; (s) the first housing member may include at least one intermediate exhaust gas orifice upstream of the diffuser member; (t) the diffuser member may include at least one intermediate exhaust gas orifice upstream of the diffuser member; (u) the second housing member may include a diffuser retainer; (v) the diffuser retainer may include a cylindrical sleeve configured to fit over the first housing member; (w) the first housing member may be substantially cylindrical, the second housing member connection portion being provided at the second end of the first housing member, and the diffuser support flange being provided at the second end of the first housing member;(x) a diffuser may be retained in the diffuser flow passage between the diffuser support flange of the first housing member, the second housing member connecting portion of the first housing member, and the diffuser retainer of the second housing member; (y) at least one exhaust gas orifice may be provided in the diffuser retainer of the second housing member or may be formed by a gap between the diffuser retainer of the second housing member and the diffuser support flange of the first housing member; and / or (z) a plurality of exhaust gas orifices may be provided in the diffuser retainer of the second housing member and / or in a gap between the diffuser retainer of the second housing member and the diffuser support flange of the first housing member;

[0122] Another aspect of one form of the present technology is a ventilation system configured to regulate a flow of pressurized breathable gas, the ventilation system including a movable membrane having an elongated shape surrounding an axis of the membrane, the membrane may be generally cylindrical, frusto-conical, or the like.

[0123] Another aspect of one form of the present technology is a vent system configured to regulate a flow of pressurized breathable gas, the vent system including a movable membrane having first and second ends spaced apart along a longitudinal axis, the membrane having a movable portion between the first and second ends surrounding the longitudinal axis, the vent system including a housing configured to restrict movement of the second end of the membrane to a surface facing the membrane.

[0124] Another aspect of one form of the present technology is a ventilation system configured to regulate a flow of pressurized breathable gas, the ventilation system including a membrane having a movable portion, the ventilation system further including a damping structure configured to damp vibrations of the movable portion of the membrane.

[0125] Another aspect of one form of the present technology is a vent system configured to regulate a flow of pressurized breathable gas, the vent system including a membrane having a movable portion, the vent system including a vent housing configured to reduce vibration of the movable portion of the membrane in vibration modes higher than a primary vibration mode.

[0126] Another aspect of one form of the present technology is a ventilation system configured to regulate a flow of pressurized breathable gas, the ventilation system including: a membrane having a movable portion having a first side and a second side; an exhaust gas flow path provided on the first side of the movable portion; and a stagnant air cavity provided on the second side of the movable portion.

[0127] Another aspect of one form of the present technology is a venting system configured to regulate a flow of pressurized breathable gas, the venting system including a membrane having a movable portion and an exhaust gas flow path including a region having a smaller cross-sectional area than an adjacent region of the exhaust gas flow path.

[0128] Another aspect of one form of the present technology is a ventilation system configured to regulate a flow of pressurized breathable gas, the ventilation system including a membrane having a first end, a second end spaced apart along a longitudinal axis, and a movable portion surrounding the longitudinal axis between the first end and the second end, the movable portion disposed radially inwardly of the longitudinal axis on an opposing surface of the membrane, with an exhaust gas flow path therebetween.

[0129] Another aspect of the present technology relates to a patient interface that may include: a seal-forming structure configured to seal against the patient's face including at least around the patient's nares; a plenum chamber connected to said seal-forming structure; a positioning and stabilizing structure for securing said patient interface on the patient in use; and a ventilation system according to any of the aspects and / or embodiments of the present technology described above.

[0130] 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.

[0131] Other features of the present technology will become apparent in light of the information contained in the following detailed description, abstract, drawings, and claims.

[0132] The present technology is illustrated by way of example and not limitation in the accompanying drawings, in which like reference numerals include like elements: [Brief explanation of the drawings]

[0133] [Figure 1A] 4.1 Treatment System. A system is shown including a patient 1000 wearing a patient interface 3000. The system 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] A system is shown including a patient 1000 wearing a patient interface 3000, which 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] The system includes a patient 1000 wearing a patient interface 3000. The patient interface 3000 takes the form of a full face mask and receives a positive pressure air supply from an RPT device 4000. 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 sleep position. 4.2 Respiratory System and Facial Anatomy [Figure 2A]4.3 Patient Interface [Figure 3A] 4.4 RPT Device [Figure 4A] 1 shows an RPT device in accordance with one form of the present technology. [Figure 4B] 4.5 Humidifiers [Figure 5A]

[0023] Fig. 10 shows an isometric view of a humidifier in accordance with one form of the present technology. [Figure 5B] FIG. 5 shows an isometric view of a humidifier in accordance with one form of the present technology, showing the humidifier reservoir 5110 removed from the humidifier reservoir dock 5130. [Figure 5C] 4.6 Respiratory Waveform [Figure 6] A model of a typical human respiratory waveform during sleep is shown. 4.7 Screening, Diagnostic and Monitoring Systems [Figure 7A] A patient undergoing polysomnography (PSG) is shown sleeping in a supine sleep position. [Figure 7B] 4.8 Ventilation System [Figure 8] 34 shows a plot of flow rate over a range of therapeutic pressures for ventilation gas flow through a ventilation system 3400 in accordance with an example of the present technology. [Figure 9A] FIG. 34 is an exploded view of a ventilation system 3400 according to an embodiment of the present technology. [Figure 9B] 9B is a side view of the ventilation system 3400 shown in FIG. 9A. [Figure 9C] 9B is a cross-sectional view of the ventilation system 3400 shown in FIG. 9A. [Figure 9D] 9B is another cross-sectional view of the ventilation system 3400 shown in FIG. 9A. [Figure 9E] 9B is another cross-sectional view of the ventilation system 3400 shown in FIG. 9A when connected to upstream and downstream components. [Figure 9F] 9B is another cross-sectional view of a portion of the ventilation system 3400 shown in FIG. 9A in use during treatment with low treatment pressure. [Figure 9G] 9B is another cross-sectional view of a portion of the ventilation system 3400 shown in FIG. 9A in use during treatment with high treatment pressure. [Figure 10A] FIG. 34 is an exploded view of a ventilation system 3400 in accordance with another embodiment of the present technology. [Figure 10B] FIG. 10B is a side view of the ventilation system 3400 shown in FIG. 10A. [Figure 10C] 10B is a cross-sectional view of the ventilation system 3400 shown in FIG. 10A. [Figure 10D] 10B is another cross-sectional view of the ventilation system 3400 shown in FIG. 10A. [Figure 11A] FIG. 34 is an exploded view of a ventilation system 3400 in accordance with another embodiment of the present technology. [Figure 11B] FIG. 11B is a side view of the ventilation system 3400 shown in FIG. 11A. [Figure 11C] 11B is a cross-sectional view of the ventilation system 3400 shown in FIG. 11A. [Figure 11D] 11B is another cross-sectional view of the ventilation system 3400 shown in FIG. 11A. [Figure 12A] FIG. 34 is an exploded view of a ventilation system 3400 in accordance with another embodiment of the present technology. [Figure 12B] FIG. 12B is a side view of the ventilation system 3400 shown in FIG. 12A. [Figure 12C] 12B is a cross-sectional view of the ventilation system 3400 shown in FIG. 12A. [Figure 12D]12B is another cross-sectional view of the ventilation system 3400 shown in FIG. 12A. [Figure 13] 10A-10C illustrate options for using the ventilation system of the present technology with a variety of patient interfaces. DETAILED DESCRIPTION OF THE INVENTION

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] In certain embodiments of the present technology, mouth breathing is restricted, limited or prevented.

[0139] 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.

[0140] 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 ventilation system 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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).

[0146] In one form, the target seal-forming area is located on an exterior surface of the seal-forming structure 3100 .

[0147] In certain forms of the present technology, the seal-forming structure 3100 is constructed from a biocompatible material (eg, silicone rubber).

[0148] A seal-forming structure 3100 according to the present technology may be constructed from a soft, flexible and resilient material (eg, silicone).

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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 area of ​​the patient's face.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] 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.

[0161] 5.3.2 Plenum chamber The plenum chamber 3200 has a periphery shaped to be complementary to the surface contours of an average human face in the area where a seal is formed in use. In use, the peripheral edge of the plenum chamber 3200 is 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.

[0162] 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.

[0163] 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.

[0164] In one form, the positioning and stabilizing structure 3300 provides a holding force sufficient to overcome the attractive force on the patient interface 3000.

[0165] 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).

[0166] 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 5.3.4 Ventilation system In one form, the patient interface 3000 includes a ventilation system 3400 constructed and arranged to allow for the expulsion of exhaled gases (e.g., carbon dioxide). The patient interface 3000 may be configured to provide respiratory therapy to the patient using a therapeutic gas flow pressurized above ambient pressure within a therapeutic pressure range via a respiratory pressure treatment device 4000. Alternatively, the ventilation system 3400 may be identified as a ventilation structure, ventilation assembly and / or vent.

[0171] In certain forms, the ventilation system 3400 is configured to allow continuous ventilation flow from the interior of the plenum chamber 3200 to atmosphere when the pressure in the plenum chamber is positive relative to atmosphere. The ventilation system 3400 is configured such that the magnitude of the ventilation flow rate is sufficient to avoid or prevent a significant amount of rebreathing of exhaled CO2 by the patient while maintaining a therapeutic pressure in the plenum chamber in use. The ventilation gas flow from the ventilation system 3400 can be continuous throughout the patient's respiratory cycle.

[0172] The vent system / vent structure 3400 may be configured (eg, sized, shaped and / or arranged) to maintain a therapeutic pressure within the plenum chamber when in use.

[0173] One form of vent system 3400 in accordance with 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).

[0174] The ventilation system 3400 may be disposed within the plenum chamber 3200. Alternatively, the ventilation system 3400 may be disposed within a decoupling structure (e.g., a swivel). In one example, as shown in FIG. 13 , the ventilation system 3400 is disposed within the air circuit 4170. The ventilation system 3400 may fluidly connect a first portion of the air circuit 4170 to a second portion of the air circuit 4170. For example, the ventilation system 3400 may fluidly connect a first portion of the air circuit 4170 connected to the RPT device 4000 to a second portion of the air circuit 4170 (e.g., ventilation connector tube 4180). The second portion of the air circuit 4170 is connected to the patient interface 3000 and is configured to provide connection with the ventilation system 3400. In another example, the ventilation system 3400 fluidly connects the patient interface 3000 to the air circuit 4170. In some examples, the ventilation system 3400 may connect the end of the air circuit 4170 to a decoupling structure 3500 (eg, a swivel elbow).

[0175] 9A-12D , a vent system 3400 according to an example of the present technology may include a vent housing 3402 and a membrane 3450. The membrane 3450 may have a non-planar shape, for example, the membrane 3450 may have a tubular shape (e.g., a cylindrical shape). The membrane 3450 may have a frusto-conical shape, for example. In some examples, the membrane 3450 may include one or more walls that are curved from one end to the other. In some examples, the membrane 3450 may have a spherical shape.

[0176] In some embodiments, the membrane 3450 includes axial symmetry. For example, the membrane 3450 is substantially symmetrical about an axis that the membrane 3450 may include. For example, the membrane 3450 may include a longitudinal axis, and the shape of the membrane 3450 may include axial symmetry about the longitudinal axis. The axial symmetry of the membrane 3450 and vent housing 3402 also facilitates use of the vent system 3400 as a connector between sections of the air circuit 4170 or between the air circuit 4170 and the patient interface 3000. Many air circuit connector components are tubular or otherwise curved, thereby providing a central pathway for therapeutic gas flow. The axial symmetry of the vent system 3400 may facilitate connections between sections of the air circuit while maintaining a similar configuration to the air circuit 4170 (e.g., a slim configuration that may not be considered excessively wide compared to the air circuit 4170). The ventilation system may provide a central passageway for therapeutic gas flow through the ventilation system 3400, and additional features of the ventilation system 3400 (e.g., exhaust gas flow paths and exhaust gas orifices) may be symmetrical about and outboard of the axis of the ventilation system 3400. The exhaust gas flow paths may be axially symmetrical and may occupy a continuous space all around within the ventilation housing.

[0177] The membrane 3450 may be configured to deform or deflect to change the cross-sectional area of ​​the exhaust gas flow path for the vent gas flow from the plenum chamber 3200 to the atmosphere.

[0178] By dynamically adjusting the cross-sectional area of ​​the exhaust gas flow path, the ventilation system 3400 can provide a substantially constant ventilation gas flow throughout a range of typical treatment pressures. By constructing the ventilation system 3400 to maintain a constant ventilation flow rate throughout a large portion of the range of typical treatment pressures, the demands on the RPT device 4000 to provide sufficient airflow to maintain the desired treatment pressure within the plenum chamber 3200, even in the presence of losses due to ventilation, for example, are reduced compared to conventional ventilation systems. The reduced demands on the RPT device 4000 allow the RPT device 4000 to remain less complex and less powerful while providing the same treatment level, thereby reducing the manufacturing costs of such devices. Several exemplary configurations of the ventilation system 3400, along with more detailed functional descriptions, are described below.

[0179] 5.3.4.1 Vented Housing 9A-9F, 10A-10D, 11A-11D, and 12A-12D show examples of different vent system 3400 configurations. In these examples, the vent system 3400 includes a vent housing 3402. The vent housing 3402 can have a first end 3404 and a second end 3405. In these examples, the first end 3404 of the vent housing 3402 and the second end 3405 of the vent housing 3402 are aligned along a longitudinal axis 3406. The interior of the vent housing 3402 is a pressurized volume 6000. In some examples of the present technology, the pressurized volume 6000 can be part of the plenum chamber 3200. In other examples, the pressurized volume 6000 can be in a different location, in which case venting of the gas flow can be required, such as in the case of the air circuit 4170. The pressurized volume 6000 can be disposed between a first portion of the air circuit 4170 and a second portion of the air circuit 4170 (eg, the vent connector tube 4180).

[0180] The vent housing 3402 may be configured to receive a gas flow from the RPT device 4000 at a first end 3404 of the vent housing 3402 and to supply a therapeutic gas flow to the patient interface 3000 at a second end 3405 of the vent housing 3402. For example, the vent housing 3402 may include an inlet 3407 for receiving the gas flow and an outlet 3408 for supplying the therapeutic gas flow. The vent housing 3402 includes at least one exhaust gas orifice that allows exhaust gas from the pressurized volume 6000 to be released to the atmosphere (indicated by reference numeral 6100). The vent gas flow may flow from the pressurized volume 6000 to the atmosphere 6100 via the at least one exhaust gas flow path 6002.

[0181] The vent housing 3402 may be configured (eg, sized, shaped and / or positioned) to maintain a therapeutic pressure within the plenum chamber 3200 during use.

[0182] The ventilation housing 3402 may include multiple diffused exhaust gas orifices 3471. In other examples, the ventilation housing 3402 may include one diffused exhaust gas orifice 3471 or any number (including zero). In these examples, the ventilation housing 3402 may also include one or more non-diffused exhaust gas orifices 3472. These non-diffused exhaust gas orifices 3472 are described in more detail below. In some examples, the ventilation system 3400 may be configured to discharge exhaust gas to a region of lower pressure than the pressurized volume 6000, but not to (or not directly to) atmosphere (e.g., the expiratory limb of the patient circuit 4170).

[0183] At least one exhaust gas orifice 3471 (eg, a single exhaust gas orifice 3471 or possibly multiple exhaust gas orifices) may be sized and shaped to maintain a therapeutic pressure within the plenum chamber 3200 in use.

[0184] As described below, the vent system includes a membrane-facing surface 3424 inside the vent housing 3402. The membrane-facing surface 3424 can be a surface of the vent housing 3402.

[0185] The vent housing 3402 may include a first housing member 3430 at a first end 3404 of the vent housing 3402 and a second housing member 3440 at a second end 3405 of the vent housing 3402. In these examples, the first housing member 3430 and the second housing member 3440 are configured to connect together. The first housing member 3430 and the second housing member 3440 may be configured to connect to each other indirectly or directly. In some examples of the present technology, the first housing member 3430 and the second housing member 3440 may be separable from each other (e.g., by a threaded connection, a friction-fit connection, a snap-fit ​​connection). In other examples, the first housing member 3430 and the second housing member 3440 may be permanently connected together (e.g., by integral formation as one component, welding, the use of a permanent snap fit, or adhesive).

[0186] 9E is connected to components of the air circuit 4170. The ventilation system 3400 is connected between the air circuit 4170 and a ventilation connector tube 4180. A ventilation housing 3402 is connected at its upstream end to an air circuit connector 4171 of the air circuit 4170 and at its downstream end to a tube connector 4182. The ventilation system 3400 receives a gas flow (indicated by 6201) from a respiratory pressure therapy (RPT) device and delivers a therapeutic gas flow (indicated by 6202) to a downstream patient interface. The ventilation system 3400 also allows for the release of a ventilation gas flow (indicated by 6203) to the atmosphere 6100. In this example, the ventilation gas flow 6203 is released entrained in a diffused ventilation gas flow (indicated by 6204) and a non-diffused ventilation gas flow (indicated by 6206).

[0187] 5.3.4.1.1 First Housing Member In these examples, the first housing member 3430 includes an inlet 3407 to the vent housing 3402. The first housing member 3430 may include an inlet connection 3416 configured to fluidly connect the vent system 3400 to a supply conduit (e.g., the air circuit 4170). The inlet connection 3416 may be provided toward (e.g., at or near) the first end 3431 of the first housing member 3430 (e.g., the upstream end of the first housing member). The inlet connection 3416 may include a bayonet fitting 3418 configured to engage with a corresponding fitting on the air circuit 4170. In other examples, the inlet connection 3416 may be configured to fluidly connect with the air circuit 4170 by other means (e.g., by a snap-fit ​​connection or a friction fit). The ventilation system 3400 shown in FIG. 9E is connected to the air circuit 4170 in one example by an air circuit connector 4171 engaged with the inlet connection.

[0188] 9C and 10C, the first housing member 3430 can include a shaft 3434 configured to protrude into the interior of the ventilation system 3400. In other examples of the present technology, the first housing member 3430 of the ventilation system 3400 does not include the shaft 3434. The shaft 3434 protrudes from the first end 3404 of the ventilation housing 3402 to the second end 3405 of the ventilation housing 3402. The shaft 3434 can be centrally disposed within the ventilation housing 3402. In these examples, the shaft 3434 extends into the pressurized volume 6000. The shaft 3434 can terminate at the second end 3432 of the first housing member 3430 (e.g., the first housing member downstream end) within the pressurized volume. The shaft 3434 is hollow with openings at each end to receive and deliver gas flow from the RPT device 4000 to the pressurized volume 6000 .

[0189] In these examples, the shaft 3434 is aligned with the longitudinal axis 3406 of the vent housing 3402. In other examples, the vent system 3400 may include a shaft 3434 that is not centered and / or extends at an angle relative to the axis of the first housing member 3430 and / or the second housing member 3440. For example, a vent system 3400 provided within a swivel elbow of the patient interface 3000 may include multiple sections with misaligned axes, thereby forming an elbow shape.

[0190] The inlet connection 3416 of the first housing member 3430 is provided on a shaft 3434. The shaft 3434 may include an outer substantially cylindrical surface at the first end 3431 of the first housing member 3430. In these examples, the bayonet fitting 3418 extends radially outward from the shaft 3434.

[0191] The membrane facing surface 3424 may be provided on the first housing member 3430. More specifically, the membrane facing surface 3422 may be provided on the outer surface 3430 of the first housing member of the vent housing 3402, the outer surface being disposed within the vent housing 3402. In the examples of FIGS. 9A-9G and 10A-10D, the membrane facing surface 3424 is provided on the shaft 3434. In these examples, the membrane facing surface 3424 is provided on the outside of the shaft 3434, facing towards the second end 3432 of the first housing member 3430 (at or near the second end 3432 of the first housing member 3430).

[0192] The membrane facing surface 3424 may include a restriction 3425 that defines an area that is smaller in cross-sectional area than adjacent areas in the exhaust gas flow path 6002. The restriction 3425 may form a restriction in the exhaust gas flow path 6002. The significance of the smaller cross-sectional area and / or restriction in the exhaust gas flow path 6002 will be discussed below. The restriction 3425 may be provided on an outer portion of the shaft 3434 toward the second end 3432 of the first housing member 3430 (e.g., at or near the second end 3432 of the first housing member 3430).

[0193] Examples of the present technology include a variety of options for the constriction. As shown in FIGS. 9C-9G, the membrane-facing surface 3424 may include a contoured surface 3425 that forms the constriction. Alternatively or additionally, the constriction 3425 may include ribs in the membrane-facing surface. The ribs that form the constriction 3425 may be provided around the periphery of the shaft 3434. Alternatively or additionally, the constriction 3425 may include an area of ​​increased material thickness in the first housing member 3430. In other examples of the present technology, the constriction 3425 may be provided on an inward-facing surface of the vent housing 3402 (e.g., where the membrane 3450 is positioned inward of the membrane-facing surface 3424).

[0194] The first housing member 3430 may include a rounded surface 3433 toward the second end 3432 of the first housing member 3430 (e.g., at or near the second end 3432 of the first housing member 3430). The rounded surface 3433 may be formed by a curved edge around the second end 3432 of the first housing member 3430. The rounded surface 3433 may provide a lower impedance to the ventilation gas flow entering the exhaust gas flow path 6002. Providing a lower impedance to the ventilation gas flow entering the exhaust gas flow path 6002 may lead to improved efficiency of the ventilation system 3400. Additionally, the rounded surface 3433 forward of the entrance to the exhaust gas flow path 6002 may help avoid gas recirculation areas within the exhaust gas flow path 6002 near the shaft end, which may result in sharper corners at the outer edge of the shaft 3434. Smooth entry into the exhaust gas flow path 6002 may be achieved by a non-curved geometry near the inlet (eg, one or more chamfers (eg, chamfered edges) on the outer periphery of the end of the shaft 3434).

[0195] The first housing member 3430 may include an outwardly protruding flange 3435. The flange 3435 may be disposed toward (e.g., at or near) the first end 3431 of the first housing member 3430. The flange 3435 may be disposed near the first end 3431 of the first housing member 3430, approximately midway between the shaft 3434 and a center point along the first end 3431 of the first housing member 3430. The flange 3435 may extend outward from the shaft 3434. The flange 3435 may be configured to connect to an exhaust gas orifice member 3470 of the ventilation system 3400. The side of the flange 3435 opposite the second end of the vent housing 3402 may be configured to connect to the exhaust gas orifice member 3470.

[0196] The flange 3435 may include a flange protrusion 3436 extending from the flange 3435 (as shown in FIG. 9B in one example). In this example, the flange protrusion 3436 is configured to connect to the exhaust gas orifice member 3470. The flange protrusion 3436 may protrude perpendicular to the flange 3435. In this example, the flange protrusion 3436 extends toward the exhaust gas orifice member 3470. The first housing member 3430 may include any number of flange protrusions 3436 (e.g., 1, 2, 3 or more). The flange protrusion 3436 may form a detachable connection (e.g., a snap-fit ​​or friction-fit connection) with the exhaust gas orifice member 3470. Alternatively, the flange projection 3436 may be permanently connected to the exhaust gas orifice member 3470 (e.g., an integrally formed or bonded snap-fit ​​connection with the exhaust gas orifice member 3470, a welded snap-fit ​​connection, or a permanent snap-fit ​​connection).

[0197] Alternatively, the membrane-facing surface 3424 may be provided on the inner surface 3430 of the first housing member, as shown in the examples of Figures 11A-11D and 12A-12D. The membrane-facing surface 3424 may have any suitable shape and configuration. For example, the membrane-facing surface 3424 is frusto-conical in the examples of Figures 11A-11D and cylindrical in Figures 12A-12D.

[0198] 5.3.4.1.2 Second housing member The second housing member 3440 may include a first end 3441 (e.g., the second housing member upstream end) and a second end 3442 opposite the first end 3441 (e.g., the second housing member downstream end).

[0199] In these examples, the second housing member 3440 includes an outlet 3408 for the supply of therapeutic gas flow. The second housing member 3440 may include an outlet connection 3420 configured to fluidly connect the ventilation system 3400 to the patient interface 3000. The outlet connection 3420 may be configured to connect directly or indirectly to the patient interface 3000. In some examples, the outlet connection 3420 may connect to a swivel elbow of the patient interface 3000 or to a portion of the air circuit 4170 (e.g., a gas supply tube) between the ventilation system 3400 and the patient interface 3000. In other examples, the outlet connection 3420 may be configured to connect to the patient interface 3000 or to a ventilation connector tube 4180 or to the patient interface 3000 (as shown in FIG. 13 ). The ventilation connector tube 4180 may be known as a “short tube.” The vent system 3400 shown in FIG. 9E is connected to a vent connector tube 4180 by a tube connector 4182 engaged with the outlet connection 3420 in one example.

[0200] The outlet connection 3420 may be configured to form a snap fit to engage with a corresponding portion of the patient interface 3000, the tube connector 4182, or the vent connector tube 4180. In the examples of Figures 9A-9G and 10A-10D, the outlet connection 3420 includes a recess 3422 configured to receive a corresponding feature (not shown) provided on the patient interface 3000, the short tube 4180, a swivel elbow, or other adapter (for connecting the outlet connection 3420 to the patient interface 3000). The corresponding feature may be, for example, a rib configured to snap fit into the recess 3422.

[0201] As described in more detail below, the second housing member 3440 may include a plurality of protrusions 3444 for limiting movement of the membrane 3450. The second housing member 3440 may include an inwardly extending membrane stop flange 3446 on which the protrusions 3444 are provided.

[0202] 5.3.4.2 Membrane The membrane 3450 may have a first end 3451 and a second end 3452 (e.g., first membrane end 3451 and second membrane end 3452). The first end 3451 of the membrane 3450 and the second end 3452 of the membrane 3450 may be spaced apart along a longitudinal axis 3454 (e.g., in an example where the membrane 3450 is cylindrical and has another axially symmetric shape). The longitudinal axis 3454 of the membrane 3450 may be aligned with the longitudinal axis 3406 of the vent housing 3402.

[0203] 5.3.4.2.1 Moving parts of the membrane 9A-12D, the membrane 3450 also includes a movable portion 3456. The movable portion 3456 of the membrane 3450 may be disposed between a first end 3451 of the membrane 3450 and a second end 3452 of the membrane 3450. In these examples, the first end 3451 of the membrane 3450 and the second end 3452 of the membrane 3450 are spaced apart along the longitudinal axis of the membrane 3450. The movable portion 3456 of the membrane 3450 may encompass the longitudinal axis of the membrane 3450 between the first end 3451 of the membrane 3450 and the second end 3452 of the membrane 3450. The movable portion 3456 may be generally centered between the first end 3451 of the membrane 3450 and the second end 3452 of the membrane 3450. The movable portion 3456 may be disposed circumferentially about the longitudinal axis of the membrane 3450. In these examples, the membrane 3450 has an elongated shape (e.g., a tubular or conical section). In other examples, the movable portion 3456 may surround the longitudinal axis of the membrane 3450 with a cross-sectional shape that is not a perfect circle, but is, for example, leaf-like or takes the form of a triangle with curved sides.

[0204] The movable portion 3456 is radially spaced from the inner membrane-facing surface 3424 of the vent housing 3402 relative to the longitudinal axis of the membrane 3450. An exhaust gas flow path 6002 is formed between the membrane-facing surface 3424 and the movable portion 3456 of the membrane 3450. A vent gas flow may flow from the pressurized volume 6000 through the exhaust gas flow path 6002 in use. In this example, the gas may flow to the atmosphere 6100 via the diffused exhaust gas orifice 3471 or the non-diffused exhaust gas orifice 3472. The exhaust gas flow path 6002 of the vent system 3400 shown in FIGS. 9A-9E may occupy a continuous space around the entire circumference within the vent housing 3402. The perimeter may be provided around the longitudinal axis of the membrane 3450. In other examples of the present technology, multiple separate exhaust gas flow paths 6002 may be provided.

[0205] 5.3.4.2.2 Movement of moving parts The movable portion 3456 of the membrane 3450 is configured to move relative to the membrane facing surface 3424. The movable portion 3456 of the membrane 3450 may be elastically deformable to move. The movable portion 3456 of the membrane 3450 is movable in one or more regions or points at which the movable portion 3456 moves. Global translation of the movable portion 3456 is not required to make the movable portion 3456 "movable." In the examples of FIGS. 9A-12D, the movable portion 3456 is movable because the material forming the movable portion 3456 can move by deformation (e.g., contraction or expansion). In other examples of the present technology, the movable portion 3456 does not deform, but instead may translate, rotate, or otherwise move. In some examples, the movable portion 3456 of the membrane 3450 is configured to move radially relative to the membrane facing surface 3424. In some examples, the movable portion 3456 of the membrane 3450 is configured to move radially inward. In other examples, the movable portion 3456 of the membrane 3450 is configured to move radially outward.

[0206] The movable portion 3456 of the membrane 3450 is configured to move relative to the membrane facing surface 3424 to vary the cross-sectional area of ​​the exhaust gas flow path 6002. The membrane 3450 is configured to regulate ventilation gas flow throughout the therapeutic pressure range.

[0207] The movable portion 3456 of the membrane 3450 can be configured to move in response to a pressure difference between the inside 3450 of the membrane and the outside 3450 of the membrane. In these examples, the movable portion 3456 of the membrane 3450 is configured to move relative to the membrane facing surface 3424 in response to a pressure change relative to the atmosphere in the pressurized volume 6000. The membrane 3450 can be exposed to a force due to the pressure of the pressurized volume 6000 on one side (e.g., the outside) of the movable portion 3456 and to a lower force due to the gas pressure in the exhaust gas flow path 6002 on the other side (e.g., the inside) of the movable portion 3456. The difference in force on either side of the movable portion 3456 of the membrane 3450 can cause the movable portion 3456 to move. In particular, the ventilation gas flow in the exhaust gas flow path 6002 may have a higher velocity and lower pressure than the gas in the pressurized volume 6000, in which case a resultant force is generated on the movable portion 3456 of the membrane 3450 in the direction of the exhaust gas flow path 6002, thereby urging the movable portion 3456 toward the membrane-opposing surface.

[0208] The lower pressure in the exhaust gas flow path 6002 compared to the pressurized volume 6000 may occur at least in part due to the effect of Bernoulli's principle. Due to the higher gas velocity in the exhaust gas flow path 6002 than in the pressurized volume 6000, less pressure is applied to the movable portion 3456 of the membrane 3450 on the side of the exhaust gas flow path 6002.

[0209] On the higher pressure side of the movable portion 3456 of the membrane 3450 (e.g., the outside in the examples shown in FIGS. 9C-9G, 10C, and 10D or the inside in the examples shown in FIGS. 11C, 11D, 12C, and 12D), the ventilation system 3400 may include a stagnant air cavity 6040 as shown in FIGS. 11C, 11D, 12C, and 12D. In these examples, the stagnant air cavity 6040 is located on a first side of the movable portion 3456 of the membrane 3450, and the exhaust gas flow path 6002 is located on a second side of the movable portion 3456 of the membrane 3450. The stagnant air cavity 6040 holds air (or other breathable gas) that is still or moving slowly compared to the air flowing in the exhaust gas flow path 6002, which may enhance the effect of Bernoulli's principle. Additionally, the stagnant air in the stagnant air cavity may be less susceptible to turbulent air movement, reducing the likelihood of vibrations occurring in the moving portion 3456 of the membrane 3450. The stagnant air cavity may also facilitate vibration damping in the moving portion 3456 of the membrane 3450.

[0210] If the treatment pressure is relatively high (e.g., 18 cmH2O), the pressure differential between the pressurized volume 6000 and the atmosphere 6100 (e.g., ambient pressure) will also be relatively high. If the movable portion 3456 of the membrane 3450 does not move at all relative to the membrane-facing surface 3424, the flow rate of the vent gas flow through the exhaust gas flow path 6002 will also be relatively high. However, if the exhaust gas flow rate is relatively high, the pressure acting on the movable portion 3456 of the membrane 3450 will be lower on the exhaust gas flow path 6002 side compared to the other side of the exhaust gas flow path 6002. As a result, the movable portion 3456 of the membrane 3450 will be forced into the exhaust gas flow path 6002 and move toward the membrane-facing surface 3424. When this occurs, the spacing between the membrane 3450 and the membrane-facing surface 3424 will decrease, thereby reducing the cross-sectional area of ​​the exhaust gas flow path 6002 through which the vent gas flow must pass. This reduced cross-sectional area impedes gas flow and avoids or minimizes the increase in flow rate that occurs when pressurized volume 6000 is at a higher pressure relative to atmosphere 6100.

[0211] 9G illustrates the deflection of the membrane 3450 during use during therapy with high treatment pressures. As shown, during respiratory therapy, ventilation gas flow 6203 flows through the movable portion 3456 of the membrane 3450 between the movable portion 3456 and the membrane-facing surface 3424 of the ventilator housing 3402. When pressure drops (relative to the air on the other side of the membrane 3450) due to higher air velocity in the exhaust gas flow path 6002, the movable portion 3456 of the membrane 3450 deflects toward the membrane-facing surface 3424. As shown, when the membrane 3450 contracts, its center is closer (along the length of the membrane 3450) to the membrane-facing surface 3424, reducing the cross-sectional area through which the ventilation gas flow must pass, thereby restricting ventilation gas flow.

[0212] At lower treatment pressures (e.g., 6 cmH2O), the pressure differential between the pressurized volume 6000 and atmosphere 6100 and the ventilation gas flow rate is lower than at higher treatment pressures. Although a low-pressure area still develops on one side of the movable portion 3456 of the membrane 3450 due to the velocity of the ventilation gas flow through the exhaust gas flow path 6002, the pressure differential across the movable portion 3456 is not as high as at higher treatment pressures. Thus, a smaller force urges the movable portion 3456 of the membrane 3450 into the exhaust gas flow path 6002 and toward the membrane-facing surface 3424 than at higher treatment pressures. As a result, impedance to ventilation gas flow is reduced at lower treatment pressures.

[0213] Figure 9F shows the deflection of the membrane 3450 during use during treatment using a lower treatment pressure than that shown in Figure 9G. Although a low-pressure region still develops between the movable portion 3456 of the membrane 3450 and the membrane-facing surface 3424, the pressure difference developed between the inside and outside of the membrane 3450 is not as great as would develop if the vent system 3400 were used at a higher treatment pressure. Thus, as shown, the movable portion 3456 of the membrane 3450 does not deflect as much as it would during treatment using a higher pressure.

[0214] The movable portion 3456 of the membrane 3450 is configured to both impede ventilation gas flow to a range dependent on the treatment pressure and to adjust ventilation gas flow throughout the treatment pressure range. Thus, the ventilation system 3400 is able to maintain a substantially constant ventilation flow rate across a typical treatment pressure range. Providing this functionality through the ventilation system 3400 reduces the need to rely on the RPT device 4000 itself to regulate and maintain a desired treatment pressure and ventilation flow rate. This reduced reliance on the RPT device 4000 for flow and pressure regulation reduces the complexity of the hardware required for the RPT device 4000 compared to RPT devices used with conventional ventilation systems. Furthermore, this similarly reduced reliance on the RPT device 4000 for flow and pressure regulation reduces the complexity of the control functions required for the RPT device 4000.

[0215] 8 shows a plot of ventilation gas flow rate through an exemplary ventilation system 3400 over a range of therapeutic pressures. As shown, over the range of therapeutic pressures from 4 to 25 cmH2O, the ventilation gas flow rate does not increase with pressure throughout the therapeutic pressure range. Instead, the flow rate increases slightly and then decreases across the therapeutic pressure range, resulting in ventilation gas flow being regulated to a nearly constant rate over the range of therapeutic pressures.

[0216] 5.3.4.2.3 Moving Part Structure In the example of the present technology shown in Figures 9A-D, the movable portion 3456 of the membrane 3450 is substantially cylindrical in shape. Forming the movable portion 3456 of the membrane 3450 cylindrical may allow for a vent housing 3402 with a smaller overall diameter than a vent housing including a membrane in a planar configuration. In other forms of the present technology, such as the vent system 3400 shown in Figures 10A-D and 11A-D, the movable portion 3456 of the membrane 3450 includes a frusto-conical shape. The frusto-conical movable portion 3456 of the membrane 3450 may also allow for a narrower vent housing 3402 than would be possible with a planar membrane. A tubular membrane may allow for a smaller overall diameter of the vent housing compared to a planar annular membrane (e.g., a disk-shaped membrane with a hole in the center).

[0217] In these examples of the present technology, the membrane 3450 and the movable portion 3456 have a longitudinal axis 3454 that is aligned substantially parallel to the direction of gas flow received from the RPT device 4000 and / or delivered to the patient interface 3000. Additionally, the movable portion 3456 of the membrane 3450 includes a wall that is aligned parallel to the direction of gas flow through the vent housing 3402 from the first end 3404 of the vent housing 3402 to the second end 3405 of the vent housing 3402. In this example, the movable portion 3456 of the membrane 3450 includes a single cylindrical wall. The longitudinal axis 3454 of this single cylindrical wall is aligned parallel to the direction of gas flow through the vent housing 3402 from the first end 3404 of the vent housing 3402 to the second end 3405 of the vent housing 3402. In other examples, the movable portion 3456 of the membrane 3450 can include multiple walls (e.g., two, three, or more) that can be non-planar and include multiple separate lobes connected at their edges, or can be planar and include multiple separate planar walls that form a hexagonal shape, octagonal shape, etc.

[0218] Because the movable portion 3456 of the membrane 3450 includes wall(s) aligned parallel to the gas flow through the vent housing 3402, the movable portion 3456 may be less susceptible to acoustic noise passing through the vent system 3400. Acoustic noise that propagates parallel to the gas flow (e.g., noise generated from the patient 1000 and returned from the patient interface 3000 along the flow path, or noise generated from the RPT device 400 traveling downstream along the flow path) may generally propagate in a direction parallel to the walls of the movable portion 3456 of the membrane 3450. When the movable portion 3456 of the membrane 3450 includes wall(s) aligned parallel to the direction in which pressure oscillates due to acoustic noise propagation, it may be less susceptible to vibrations due to the noise compared to wall(s) aligned perpendicular to the propagation direction. That is, wall(s) aligned parallel to the gas flow through the ventilation system 3400 may be less susceptible to noise than wall(s) aligned perpendicular to the flow in the ventilation system 3400. Thus, the movable portion 3456 of the membrane 3450 may transmit lower acoustic noise levels, at least compared to the movable portion 3456 of the membrane 3450 having wall(s) perpendicular to the flow (e.g., a planar annular membrane (e.g., a disk-shaped membrane with a hole in the center)). Thus, the ventilation system 3400 may be relatively quieter, or at least quieter, than alternative arrangements.

[0219] The movable portion 3456 of the membrane 3450 may be formed from silicone. In other examples, the movable portion 3456 of the membrane 3450 may be formed from another suitable material (e.g., rubber or a thermoplastic elastomer).

[0220] 9C-9G, 10C, and 10D, the membrane 3450 can be attached to the outside of the membrane facing surface 3424. In these examples, the movable portion 3456 of the membrane 3450 is provided around the periphery of the membrane facing surface 3424. In these examples, the membrane 3450 and the membrane facing surface 3424 are concentric (e.g., share a common axis).

[0221] 9A-9G and 10A-10D, the movable portion 3456 of the membrane 3450 is configured to move inward to restrict vent gas flow. More specifically, the movable portion 3456 of the membrane 3450 may be configured to contract and move inward toward the membrane-facing surface 3424. In other examples of the present technology, such as the examples of FIGS. 11A-11D and 12A-12D, the movable portion 3456 of the membrane 3450 is configured to move outward toward the membrane-facing surface. However, when the vent system 3400 includes a cylindrical or frustoconical membrane 3450, an advantage of the movable portion 3456 of the membrane 3450 moving inward (e.g., contracting) is that this movement does not induce hoop stress in the movable portion 3456 of the membrane 3450. That is, as the movable portion 3456 moves radially inward, the cylindrical membrane 3450 may deform into an hourglass shape. As a result, less force (e.g., a smaller pressure differential across the membrane 3450) may be required to move the membrane 3450 inward rather than outward. This additional hoop stress may also cause the movable portion 3456 of the membrane 3450 to become more unstable (when moving outward than when moving inward). FIGS. 9F and 9G show how the membrane 3450 deflects by different amounts. As shown in FIG. 9F, the movable portion 3456 of the membrane 3450 has moved less toward the membrane-facing surface 3424 (as may occur during treatment with a lower treatment pressure), while in FIG. 9G, the movable portion 3456 of the membrane 3450 has moved more toward the membrane-facing surface 3424 (as may occur during treatment with a higher treatment pressure).

[0222] While moving the membrane 3450 inward can be advantageous, the membrane 3450 included in the ventilation system 3400 included in the present technology has a movable portion 3456 that moves outward toward the membrane-facing surface. In such an example, as shown in FIGS. 11A-11D and 12A-12D, the movable portion 3456 of the membrane 3450 can be supported inside the membrane-facing surface 3424. Thus, the movable portion 3456 of the membrane 3450 can move outward to restrict ventilation gas flow. The movable portion 3456 of the membrane 3450 can be configured to expand and move toward the membrane-facing surface 3424. If the membrane 3450 has a cylindrical shape, the membrane 3450 can expand outward as the movable portion 3456 moves radially outward.

[0223] In some examples, the membrane 3450 may include a planar structure. While the use of a generally tubular membrane 3450 provides certain advantages in the vent system 3400, other advantageous features of the vent system 3400 of the present technology may be applied to a vent system 3400 having a planar membrane 3450. For example, the stagnant air cavity 6040, the damping chamber 6050, and / or the vent housing 3402 (which, as described above, reduce vibration of the membrane 3450 in modes higher than the first mode) are features that may be applied to a vent system 3400 having a planar membrane. One example of a planar membrane 3450 is a disk with a hole in the center (e.g., in the shape of a flat washer).

[0224] 5.3.4.3 Membrane stop The vent housing 3402 may be configured to limit movement of the movable portion 3456 of the membrane 3450 toward the membrane-facing surface 3424. Preventing too much movement of the movable portion 3456 of the membrane 3450 toward the membrane-facing surface 3424 may advantageously avoid excessive impedance to the vent gas flow or blockage of the exhaust gas flow path 6002.

[0225] The vent housing 3402 may contact the end of the membrane 3450 and prevent the end of the membrane 3450 from moving toward the membrane facing surface 3424. The vent housing 3402 may include or provide one or more membrane stops configured to limit movement of the movable portion 3456 of the membrane 3450. In the examples shown in FIGS. 9A-9G, 10A-10D, 11A-11D, and 12A-12D, the vent housing 3402 contacts the second end 3452 of the membrane 3450 and prevents the second end 3452 of the membrane 3450 from moving toward the membrane facing surface 3424. In this example, the vent housing 3402 includes at least one protrusion 3444. The at least one protrusion 3444 contacts an edge of the membrane 3450 to limit movement of the edge of the membrane 3450 (eg, the second end 3452 of the membrane 3450).

[0226] The vent housing 3402 may include a plurality of protrusions 3444. The protrusions 3444 may be known as stoppers. In other examples, the vent housing 3402 may include other types of membrane stops (e.g., an inner ring with a plurality of holes that contacts the movable portion 56 in front of the membrane 3450 and allows air to enter the exhaust gas flow passage 6002 or the damping chamber 6050). In further examples, the membrane stops may be provided on the membrane 3450 itself. Furthermore, in some examples, the membrane 3450 may be configured to limit its own movement or have an end that cannot substantially move or deform. In one example, the free end of the membrane 3450 may include a substantially rigid portion that cannot deform or move toward the membrane-facing surface 3424.

[0227] 9A-9G and 10A-10D, one or more protrusions 3444 are located outside the exhaust gas flow path 6002. By locating the protrusions 3444 outside the exhaust gas flow path 6002, in these examples, the ventilation gas flow does not pass around or between the protrusions 3444 (as it flows to the atmosphere 6100). An advantage of locating the protrusions 3444 outside the exhaust gas flow path 6002 is that the flow is not obstructed by the protrusions 3444. In examples where the protrusions 3444 are located within the exhaust gas flow, the protrusions 3444 within the flow path may create wakes in the ventilation gas flow downstream of the protrusions, which may create turbulence and result in increased noise from the ventilation system 3400. Additionally, turbulence in the ventilation flow may cause the movable portion 3456 of the membrane 3450 to resonate or otherwise vibrate, which may further increase the noise level of the ventilation system 3400.

[0228] In the example of the vent system 3400 shown in FIGS. 9A-9G and 10A-10D, the second housing member 3440 includes a plurality of protrusions 3444. The protrusions 3444 may be disposed inwardly of the membrane 3450. In these examples, the protrusions 3444 protrude into the first end 3404 of the vent housing 3402. The second housing member 3440 may include an inwardly extending membrane stop flange 3446 on which the protrusions 3444 are provided. The protrusions 3444 may protrude from the membrane stop flange 3446 in a direction toward the first end 3404 of the vent housing 3402. One or more of the protrusions 3444 may contact the inner surface 3450 of the membrane 3450 at the second end 3452 of the membrane. In this manner, inward movement of the second end 3452 of the membrane 3450 is limited by the protrusion 3444 .

[0229] In another example of the present technology, the vent housing 3402 may include only one protrusion 3444 (e.g., in the form of one or more lips configured to fit snugly into or around the second end of the membrane 3450). However, an advantage of multiple protrusions 3444 is that the multiple protrusions 3444 may define openings between adjacent pairs. Damping orifices 6055 may be included between the protrusions 3444, as will be described in further detail below.

[0230] Despite the location of the protrusions 3444 outside the vent gas flow, an advantage is that in some instances, the protrusions 3444 or other membrane stops may be located within the vent flow (e.g., within the exhaust gas flow path 6002). The example vent system 3400 shown in Figures 11C, 11D, 12C, and 12D includes protrusions 3444 on the membrane-facing surface 2424. The protrusions 3444 may take the form of stops, protrusions, ridges, standoffs, tongues, etc. The protrusions 3444 contact portions of the movable portion 3456 of the membrane 3450 to hold the movable portion 3456 away from the membrane-facing surface 3424 and avoid blockage of the exhaust gas flow path 6002.

[0231] At least one protrusion 3444 may be provided on the first housing member 3430. In the example of FIGS. 11A-12D, multiple protrusions 3444 are provided on the inner surface of the first housing member 3430 to limit movement of the second end 3452 of the membrane 3450 toward the membrane-facing surface 3424 of the first housing member 3430. In these examples, the protrusions 3444 protrude radially inward from the cylindrical surface (in the example of FIGS. 12A-12D) or the conical surface (in the example of FIGS. 11A-11D) of the first housing member 3430. The protrusions 3444 may contact the outer surface of the membrane 3450 at the second end 3452 of the membrane 3450.

[0232] 5.3.4.4 Membrane support The membrane 3450 is supported within the vent housing 3402 on a membrane support 3460, which may be included in the vent system 3400. The membrane support 3460 may be a rigid structure supported by or within the vent housing 3402 and configured to support the membrane and hold the first end 3451 of the membrane 3450 in place. In these examples, the membrane 3450 may be molded to the membrane support 3460 at the first end 3451 of the membrane 3450. In other examples, the membrane 3450 may be molded to the membrane support 3460 at the second end of the membrane 3450. In some examples of the present technology, the membrane 3450 may be attached to the membrane support 3460 without any permanent connection thereto. The membrane 3450 may be attached, for example, around the periphery of a cage or other substantially rigid structure.

[0233] In these examples, the membrane support 3460 can be configured to connect to the vent housing 3402. In these examples, the membrane support 3460 is configured to connect to the vent housing 3402 between the first end 3404 of the vent housing 3402 and the second end 3405 of the vent housing 3402. The membrane support 3460 can be configured to connect to the center of the vent housing 3402, as shown in FIGS. 9C-9G, 10C, and 10D. Alternatively, as shown in FIGS. 11C, 11D, 12C, and 12D, the membrane support 3460 can be configured to connect the vent housing 3402 to the first end 3404 of the vent housing 3402 (e.g., at or near the first end 3404 of the vent housing 3402). In some forms of the present technology, when the orientation of the membrane 3450 is reversed, the membrane support 3460 can be configured to connect to the vent housing 3402 at the second end 3405 of the vent housing 3402 (e.g., at or near the second end 3405 of the vent housing 3402).

[0234] 9A-9G, the membrane support 3460 can include a connection portion 3462 for connection to the vent housing 3402. The connection portion 3462 can be configured to connect directly or indirectly to the vent housing 3402. The connection portion 3462 can be cylindrically shaped and configured to fit around the outside of the second housing member 3440. The connection portion 3462 can be concentric with the membrane 3450.

[0235] The membrane support portion 3460 may include a membrane support flange 3464 extending inward from an inner surface of a connecting portion 3462 of the membrane support portion 3460 configured to support the membrane 3450. The membrane support flange 3464 may be spaced apart from an end of the connecting portion 3462. The membrane 3450 may be molded to the membrane support flange 3464. As shown in the example of FIGS. 9A-9G, the membrane support flange 3464 supports the membrane 3450 inside the vent housing. In this example, the first end 3451 of the membrane 3450 is secured to and supported on the membrane support flange 3464. Thus, the membrane support flange 3464 supports the first end 3451 of the membrane 3450 inside the vent housing 3402, and the membrane 3450 extends from the membrane support flange 3464 to the second end 3405 of the vent housing 3402.

[0236] The membrane support portion 3460 may include a baffle portion 3465, as shown in the examples in FIGS. 11A-11D and 12A-12D. The baffle portion 3465 is configured to block one side of the membrane 3450 from gas flow through the center of the vent housing 3402. In these examples, the movable portion 3456 of the membrane 3450 moves outward toward the membrane-facing surface 3424 to restrict gas flow through the exhaust gas flow passage 6002. In these examples, the baffle portion 3465 is cylindrical. In other examples, the baffle portion 3465 may be frusto-conical, bell-shaped, or any other suitable shape. The baffle portion 3465 may be concentric with the movable portion 3456 of the membrane 3450. In these examples, the baffle portion 3465 is disposed radially inward of the movable portion 3456 of the membrane 3450. 11A-12D, the baffle portion 3465 has a first end 3466. The first end 3466 is connected to the movable portion 3456 of the membrane 3450 at the first end 3451 of the membrane 3450. Additionally, the baffle portion 3465 has a second end 3467. The second end 3467 is disposed toward the second end 3452 of the membrane 3450 (e.g., at or near the second end 3452 of the membrane 3450).

[0237] 11A-11D , the baffle portion 3465 includes a baffle flange 3468 at a second end 3467 of the baffle portion 3465. In this example, the baffle flange 3468 extends outward from the baffle portion 3465. The baffle flange 3468 may partially define the exhaust gas flow path inlet 6004 to the exhaust gas flow path 6002.

[0238] The rounded surface 3433 at or near the exhaust gas flow path inlet 6004 can be a curved edge at its second end of the membrane support 3460. The rounded surface 3433 can be provided on a baffle flange 3468 of the membrane support 3460, as shown in Figures 11A-11D.

[0239] The damping chamber 6050 may be defined in part by the baffle portion 3465 of the membrane support portion 3460. The damping chamber 6050 may be defined in part by an outwardly extending flange of the baffle portion 3465.

[0240] 5.3.4.5 Exhaust gas flow Ventilation gas flow may flow radially outward at or near the entrance to the exhaust gas flow path 6002. In the examples of Figures 9A-9G, 10A-10D, 11A-11D, and 12A-12D, and with particular reference to Figure 9E which illustrates various gas flows, gas flow 6201 from the RPT device 4000 to the patient interface 3000 flows axially through the vent housing 3402. Additionally, a portion of gas flow 6201 into the vent housing 3402 becomes vent gas flow 6203 and flows radially at or near the entrance to the exhaust gas flow path 6002. The direction of gas flow within the vent housing 3402 may change from axial to radial, thereby creating vent gas flow 6203. During or before passing through the inlet to the exhaust gas flow path 6002, the vent gas flow 6203 may change direction from a radial direction to an axial direction aligned with the longitudinal axis of the vent system 3400. The vent gas flow in the exhaust gas flow path 6002 may flow parallel to the longitudinal axis 3406 of the vent housing 3402 and / or the longitudinal axis 3454 of the membrane 3450.

[0241] As described in more detail above, the vent housing 3402 may include a rounded surface 3433 at or near the entrance to the exhaust gas flow path 6002 (e.g., at the exhaust gas flow path inlet 6004). The rounded surface 3433 may be configured to promote redirection of vent gas flow ahead of the entrance to the exhaust gas flow path 6002. More specifically, the vent housing 3402 may include an exhaust gas flow path 6002 having an exhaust gas flow path inlet 6004 that is shaped to avoid high resistance to gas flow entering the exhaust gas flow path 6002. This shape may be achieved by the rounded surface 3433 on the first housing member 3430 or a curved or other contoured surface on another portion of the vent housing 3402 or one of the components of the vent system 3400 (e.g., the second housing member 3440 in the example of FIGS. 11A-11D ).

[0242] The exhaust gas flow path inlet 6004 can be an annular opening in the vent housing 3402. For example, in the example of Figures 9A-10D, the exhaust gas flow path inlet 6004 extends into the exhaust gas flow path 6002 around the outside of the first housing member 3430. The first housing member 3430 and the membrane 3450 are concentric with one another, but at the second end 3432 of the first housing member 3430, the inner diameter of the membrane 3450 is larger than the outer diameter of the first housing member 3430, thereby providing a gap that forms the exhaust gas flow path inlet 6004.

[0243] In some examples, the exhaust gas flow path inlet 6004 may be defined by the axial spacing between components. In the example shown in FIGS. 9A-10D , the opening forming the exhaust gas flow path inlet 6004 may be provided by the axial spacing between a portion of the first housing member 3430 and a portion of the second housing member 3440 within the vent housing 3402. In the example shown in FIGS. 11A-11D , the exhaust gas flow path inlet 6004 is primarily defined by the axial spacing between the membrane support member 3460 and the vent housing 3402. Specifically, the exhaust gas flow path inlet 6004 is defined by the axial spacing between the membrane support member 3460 and the second housing member 3440 in the example shown in FIGS. 11A-11D .

[0244] 12A-12D, the vent housing 3402 includes multiple exhaust gas flow path inlets 6004. In this example, the multiple exhaust gas flow path inlets 6004 are formed in the membrane support portion 3460 (specifically, in the baffle portion 3465). In other examples, the multiple exhaust gas flow path inlets 6004 may be provided in other locations. The multiple exhaust gas flow path inlets 6004 may be provided by openings formed in, for example, the baffle flange 3468. In a further example, the multiple exhaust gas flow path inlets 6004 may be provided by openings formed in the first housing member 3430 (e.g., in the shaft 3434).

[0245] The vent housing 3402 may include a plurality of exhaust gas orifices 3471 and 3472 configured to allow exhaust gas transfer to the atmosphere 6100. The exhaust gas orifices may be spaced apart around the periphery of the vent housing 3402. The vent housing 3402 may include at least one diffused exhaust gas orifice 3471 and at least one non-diffused exhaust gas orifice 3472. In the example of FIGS. 9 and 11, the vent housing 3402 includes a plurality of diffused exhaust gas orifices 3471 and a plurality of non-diffused exhaust gas orifices 3472.

[0246] The ventilation system 3400 may include a diffuser member 3474 configured to diffuse and / or attenuate the exhaust gases as they exit the ventilation system 3400. In other examples, the ventilation system 3400 may include multiple diffuser members 3474. The diffuser member 3474 may be formed from a fibrous mesh through which the exhaust gases may be forced to follow a tortuous path (e.g., a felt material). Other materials that diffuse and / or attenuate the vent gas flow may be used in the ventilation system 3400 (e.g., open-cell foam).

[0247] The diffuser member 3474 may be positioned in series with (e.g., above or after) the at least one diffusional exhaust gas orifice 3471 such that gas flowing through the at least one diffusional exhaust gas orifice 3471 passes through the diffuser member 3474. The at least one non-diffusional exhaust gas orifice 3472 may be open (e.g., not blocked by the diffuser member).

[0248] As shown in Figures 9A-9G, 11A-11D, and 12A-12D, with particular reference to Figure 9E, which illustrates the specific gas flow paths and diffuser member 3474, the diffusing ventilation flow path provided by the ventilation system 3400 allows exhaust gas to vent through the diffuser member 3474 and at least one diffusing exhaust gas orifice 3471. In Figure 9E, the diffusing gas flow is indicated by 6204. Additionally, the non-diffusing ventilation flow path provided by the ventilation system 3400 allows exhaust gas to vent through at least one non-diffusing exhaust gas orifice 3472 in the examples of Figures 9A-9G and 11A-11D. In Figure 9E, the non-diffusing gas flow is indicated by 6205.

[0249] If the exhaust gas cannot pass through the diffuser member 3474 and the at least one diffusing exhaust gas orifice 3471, the ventilation system 3400 can be configured to cause the exhaust gas to flow through the at least one non-diffusing exhaust gas orifice 3472. Advantageously, the ventilation system 3400 in the examples of FIGS. 9A-9G and 11A-11D can vent the exhaust gas if the diffuser member 6474 becomes clogged, blocked, or otherwise unable to allow sufficient vent gas flow therethrough. As shown in FIG. 9E, the vent gas flow 6203 flows through the exhaust gas flow path 6002. The vent gas flow 6203 can then bypass the diffuser member 3474 by either flowing as a diffused vent gas flow 6204 through the diffuser member 3474 to the atmosphere 6100 or flowing directly to the atmosphere 6100 as a non-diffusing vent gas flow 6205. Which path the ventilation gas flow takes may depend on whether the diffuser member 3474 is clogged or not.

[0250] 9A-9G and 11A-11D, when the diffuser member 3474 is not clogged and allows sufficient ventilation flow through the diffusing exhaust gas orifice 3471, the vent housing 3402 provides a higher resistance (compared to the diffusing exhaust gas orifice 3471) to ventilation flow through the non-diffusing exhaust gas orifice 3472. Thus, when the diffuser member 3474 is activated (e.g., unblocked), a majority of the ventilation flow passes through the diffuser member 3474 and through the diffusing exhaust gas orifice 3471 as the diffused ventilation gas flow 6204. When the diffuser member 3474 is clogged and provides increased resistance to gas flow, the vent housing still allows ventilation gas flow through the non-diffusing exhaust gas orifice 3472 as the non-diffusing ventilation gas flow 6205.

[0251] The vent housing 3402 may be shaped to require a greater change in exhaust gas flow direction as it passes through the at least one non-diffusional exhaust gas orifice 3472 than as it passes through the diffusional exhaust gas orifice 3471. The greater change in direction required upon exiting the non-diffusional exhaust gas orifice 3472 provides sufficient resistance to force the gas through the diffuser member 3474 (rather than through the non-diffusional exhaust gas orifice 3472). That is, the vent housing 3402 may be shaped to require a change in exhaust gas flow direction through the non-diffusional exhaust gas orifice 3472 to a sufficient extent that a majority of the exhaust gas flow passes through the diffuser member 3474 and the diffusional exhaust gas orifice 3471 unless the diffuser member 3474 becomes clogged.

[0252] The vent housing 3402 may be shaped such that the exhaust gas must turn approximately 90 degrees to flow through one or more of the diffusion-type exhaust gas orifices 3471, as shown in Figures 9C and 9D. Similarly, as shown in Figures 9C and 9D, the vent housing 3402 may be shaped such that the exhaust gas must turn more than 90 degrees to flow through one or more of the non-diffusion-type exhaust gas orifices 3472. In various examples, the vent housing 3402 may be shaped such that the exhaust gas must turn more than 110 degrees, 130 degrees, or 150 degrees to flow through one or more of the non-diffusion-type exhaust gas orifices 3472.

[0253] The diffused exhaust gas orifice 3471 and the non-diffused exhaust gas orifice 3472 may be longitudinally spaced apart along the length of the vent housing 3402. In the examples of Figures 9A-9G and 11A-11D, the diffused exhaust gas orifice 3471 is positioned toward (e.g., at or near) the first end 3404 of the vent housing 3402. In these examples, the non-diffused exhaust gas orifice 3472 is centrally positioned between the first end 3404 of the vent housing 3402 and the second end 3405 of the vent housing 3402.

[0254] The diffusion type exhaust gas orifices 3471 may open laterally (i.e., radially) relative to the vent housing 3402. The exhaust gas may be highly diffused after passing through orifices that open laterally from the periphery of the vent housing 3402 because the exhaust gas may be diffused over a gradually larger area as it travels away from the vent housing 3402. The non-diffusion type exhaust gas orifices 3472 may open partially laterally and partially toward the second end 3405 of the vent housing 3402 (i.e., at an oblique angle relative to the longitudinal axis 3402 of the vent housing).

[0255] In some examples, the ventilation system 3400 may include a diffuser member 3474 configured to diffuse and / or muffle the ventilation gas flow and may include one or more common exhaust gas orifices 3473 through which the ventilation flow gas may travel to the atmosphere 6100 regardless of whether flow is permitted within the diffuser member 3474.

[0256] As shown in FIGS. 10A-10D, the ventilation system 3400 includes a first housing member 3430. The first housing member 3430 includes a flange 3435 and a diffuser carrying rim 3437. Held in place by the flange 3435 and the diffuser carrying rim 3437 is a diffuser member 3474. The diffuser member 3474 is positioned adjacent to and spaced from the membrane support 3460 in the gas flow path through the exhaust gas flow path 6002 downstream of the membrane 3450. In this example, the ventilation system 3400 includes a low-resistance flow path. When the diffuser member 3474 is unclogged, this low-resistance flow path extends from the common exhaust gas orifice 3473 after passing through the material of the diffuser member 3474. Furthermore, in this example, the ventilation system 3400 includes a high resistance flow path (when the diffuser member 3474 is not clogged) that requires the gas flow to make a sharp turn downstream of the membrane 3450 (in this example, at the first end 3451 of the membrane 3450) before passing through the diffuser member 3474 and exiting to the atmosphere through the common exhaust gas orifice 3473.

[0257] 10A-10D, when the diffuser member 3474 is not clogged, the majority of the ventilation gas flow takes the low resistance path through the diffuser member 3474. If the diffuser member 3474 becomes clogged or otherwise does not allow sufficient flow therein, the ventilation system 3400 can still function because the exhaust gas can flow through other paths through the diffuser member 3474 that provide a lower resistance path when the diffuser member 3474 is clogged.

[0258] The ventilation system 3400 may include at least one intermediate exhaust gas orifice 3478 upstream of the diffuser member 3474. In the example of FIGS. 12A-12D , the first housing member 3430 includes multiple intermediate exhaust gas orifices 3478. The intermediate exhaust gas orifices 3478 are provided upstream of the diffuser member 3474. The intermediate exhaust gas orifices 3478 may or may not be covered by the diffuser member 3474. In the example shown in FIGS. 11A-11D , the diffuser member 3474 does not cover the intermediate exhaust gas orifices 3478, so that the ventilation gas flow may pass through the diffuser member 3474 and then through the diffusing exhaust gas orifice 3471, or through the non-diffusing exhaust gas orifice 3472 after passing through the diffuser member 3474.

[0259] 12A-12D, the diffuser member 3474 covers the intermediate exhaust gas orifices 3478. In this example, the diffuser member 3474 is substantially cylindrically shaped to fit snugly around a portion of the vent housing 3402. The diffuser member 3474 covers the intermediate exhaust gas orifices 3478 to diffuse and / or attenuate the vent gas flow from the intermediate exhaust gas orifices 3478. Gases can be vented through the diffused exhaust gas orifices 3471 and through the diffuser member 3474 to the atmosphere.

[0260] 12A-12D, the diffused exhaust gas orifice 3471 is also formed by a gap between a portion of the first housing member 3430 and the first end 3441 of the second housing member 3440. Generally, in any example of the present technology, the exhaust gas orifice (diffused or non-diffused) may be formed by a hole or opening formed in a single component of the vent housing 3402 (e.g., the first housing member or the second housing member), or may be formed by a gap formed between multiple components of the vent housing 3402.

[0261] The second housing member 3440 may include a diffuser retaining portion 3448. In this example, the diffuser retaining portion 3448 takes the form of a cylindrical sleeve configured to fit over the first housing member 3430. The first housing member 3430 also has, in this example, a substantially cylindrical second housing member connecting portion 3438 at the second end 3432 of the first housing member 3430 and a diffuser retaining rim 3437. The diffuser takes the form of a flange at the second end 3432 of the first housing member 3430. In this example, the diffuser member 3474 is held in place radially by the diffuser retaining portion 3448 of the second housing member 3440 while being held within a channel of the first housing member 3430 between the diffuser retaining rim 3437 and the second housing member connecting portion 3449.

[0262] In the example of Figures 12A to 12D, the diffusion type exhaust gas orifice 3471 formed by the gap between the first housing member 3430 and the second housing member 3440 is formed by the gap between the diffuser retaining portion 3448 of the second housing member 3440 and the diffuser retaining rim 3437 of the first housing member 3430.

[0263] 5.3.4.6 Exhaust gas orifice member The ventilation system 3400 may include an exhaust gas orifice member 3470 that includes one or more exhaust gas orifices through which the ventilation gas flow can exit the ventilation system 3400 and travel to the atmosphere 6100.

[0264] The ventilation system 3400 shown in Figures 9A-9G and 11A-11D includes an exhaust gas orifice member 3470. In these examples, the exhaust gas orifice member 3470 includes a plurality of exhaust gas orifices. At least one diffusive exhaust gas orifice 3471 may be disposed toward (e.g., at or near) a first end 3476 of the exhaust gas orifice member 3470. In these examples, the diffusive exhaust gas orifice 3471 is disposed substantially at the first end 3476 of the exhaust gas orifice member 3470. The one or more non-diffusion type exhaust gas orifices 3472 may be provided toward a second end 3477 of the exhaust gas orifice member 3470 opposite the first end 3476 of the exhaust gas orifice member 3470 (e.g., at or near the second end 3477 of the exhaust gas orifice member 3470). The exhaust gas orifice member 3470 of the ventilation system 3400 shown in Figures 9A-9G includes a plurality of diffusion type exhaust gas orifices 3471 toward the first end 3476 of the exhaust gas orifice member 3470 (e.g., at or near the first end 3476) and a plurality of non-diffusion type exhaust gas orifices 3472 toward the second end 3477 of the exhaust gas orifice member 3470 (e.g., at or near the second end 3477).

[0265] As shown in the examples of FIGS. 9A-9G and 11A-11D, the exhaust gas orifice member 3470 may be configured to connect to the first housing member 3430. The exhaust gas orifice member 3470 may be formed in a ring shape. In the example of FIG. 9, a diffusion-type exhaust gas orifice 3471 is formed in the exhaust gas orifice member 3470 and opens laterally, radially outward from the axis of the exhaust gas orifice member 3470. Furthermore, a non-diffusion-type exhaust gas orifice 3472 is formed in the exhaust gas orifice member 3470 and opens partially radially and partially axially relative to the exhaust gas orifice member 3470. In this example, the non-diffusion-type exhaust gas orifice 3472 opens obliquely to the lateral direction, while the diffusion-type exhaust gas orifice 3471 opens in this lateral direction. In this manner, the exhaust gas orifices opening in different directions contribute to the different flow path resistance that the ventilation flow may have as it exits the ventilation system 3400, as further detailed above.

[0266] 9A-9G and 11A-11D, the diffuser member 3474 is retained within the ventilation system 3400 by the exhaust gas orifice member 3470. In these examples, the diffuser member 3474 is housed between the exhaust gas orifice member 3470 and the first housing member 3430.

[0267] 9A-9G are configured to connect together and thereby connect to the first housing member 3430 and the second housing member 3440. Specifically, the connection portion 3462 of the membrane support portion 3460 is configured to connect to the exhaust gas orifice member 3470. The connection portion 3462 of the membrane support portion 3460 may be configured to form a press-fit connection with the exterior of the exhaust gas orifice member 3470. When the membrane support portion 3460 is connected to both the exhaust gas orifice member 3470 and the second housing member 3440, a membrane support flange 3464 may be provided between the exhaust gas orifice member 3470 and the second housing member 3440.

[0268] 5.3.4.7 Vibration reduction 5.3.4.7.1 Damping structure 9A-10D includes a damping structure configured to dampen vibrations of the movable portion 3456 of the membrane 3450. In these examples, the damping structure includes a damping chamber 6050 within the vent housing 3402. By damping vibrations of the movable portion 3456, the damping chamber 6050 may be able to reduce noise radiated from the vent system 3400 and emanating from the membrane 3450. The damping chamber 6050 may contain stagnant air (or other breathable gas). In these examples, the damping chamber 6050 is a stagnant air cavity.

[0269] The vent housing 3402 may partially define a damping chamber 6050. Additionally, the membrane 3450 may partially define the damping chamber 6050. As shown in FIGS. 9C-9G, 10C, and 10D, the damping chamber 6050 is a cavity provided on the outside of the membrane 3450, which is in fluid communication with the pressurized volume 6000 during use and is filled with gas at the same pressure as the pressurized volume 6000 when the membrane 3450 is at rest. The movable portion 3456 of the membrane includes a first side facing the membrane-facing surface 3424 and a second side opposite the first side. The second side partially defines the damping chamber 6050. The damping chamber 6050 may be further defined by one or more walls of the second housing member 3440. In various examples, one of the inner and outer sides of the movable portion 3456 of the membrane 3450 faces the membrane-facing surface 3424 , and the other of the inner and outer sides of the movable portion 3456 of the membrane 3450 partially defines the damping chamber 6050 .

[0270] The vent system 3400 may be configured such that the volume 6050 of the damping chamber increases or decreases due to movement of the movable portion 3456 of the membrane 3450. The change in volume of the damping chamber 6050 reduces the amount of air that can occupy the damping chamber 6050 at a particular pressure.

[0271] In these examples, the vent housing 3402 and damping chamber 6050 are configured to damp vibrations of the movable portion 3456 of the membrane 3450 by restricting gas exchange between the damping chamber 6050 and the pressurized volume 6000. The restriction in gas exchange between the damping chamber 6050 and the pressurized volume 6000 provides a damping effect on the membrane 3450 as the movable portion 3456 of the membrane 3450 moves, resulting in an increase or decrease in the volume of the damping chamber 6050. As shown in FIGS. 9C-9G, the vent system 3400 can include at least one damping orifice 6055. The at least one damping orifice 6055 allows gas to flow in and out of the damping chamber 6050. The damping chamber gas flow into the damping chamber 6050 is indicated by 6206 in FIGS. 9F and 9G. The damping orifice 6055 may be shaped and / or sized to tolerate gas exchange between the damping chamber 6050 and the pressurized volume 6000 .

[0272] As the movable portion 3456 of the membrane 3450 begins to move away from the membrane facing surface 3424, the volume of the damping chamber 6050 decreases, restricting gas flow out of the damping chamber 6050 and resulting in an increase in gas pressure within the damping chamber 6050. This increase in pressure within the damping chamber 6050 acts on the movable portion 3456 of the membrane 3450, slowing the movement of the movable portion 3456 of the membrane 3450 away from the membrane facing surface 3424.

[0273] Conversely, when the movable portion 3456 of the membrane 3450 begins to move towards the membrane facing surface 3424, the resulting increase in the volume of the damping chamber 6050 restricts the flow of gas into the damping chamber 6050, resulting in a decrease in the gas pressure within the damping chamber 6050. This decrease in pressure in the damping chamber 6050 acts on the movable portion 3456 of the membrane 3450, slowing the movement of the movable portion 3456 of the membrane 3450 towards the membrane facing surface 3424.

[0274] In these examples, the restriction to gas flow between the pressurized volume 6000 and the damping chamber 6050 is not a complete occlusion that prevents all gas exchange. The restriction to gas exchange within or outside the damping chamber 6050 may allow for slowing and / or smoothing of the movement of the movable portion 3456 of the membrane 3450. However, the restriction to gas exchange allows for movement of the movable portion 3456 of the membrane 3450 due to non-oscillatory forces as the pressure difference between the pressurized volume 6000 and the damping chamber 6050 equalizes over time. For example, when a constant force is applied on the movable portion 3456 of the membrane 3450 toward the membrane-facing surface 3424, the damping chamber 6050 may initially slow and / or smooth the movement of the movable portion 3456 of the membrane 3450 toward the membrane-facing surface 3424. 9G, the pressure in the damping chamber 6050 equalizes with the pressure in the pressurized volume 6000. The movable portion 3456 of the membrane 3450 then occupies a position closer to the membrane-facing surface 3424 without being pulled back by the lower pressure in the damping chamber 6050. Thus, a damping effect is achieved that resists and / or smooths out unwanted movement of the movable portion 3456 of the membrane 3450 (e.g., vibrations that may generate noise).

[0275] As described above, the vent system 3400 can include at least one damping orifice 6055. The at least one damping orifice 6055 can be small enough to withstand constant gas exchange between the damping chamber 6050 and the pressurized volume 6000. The damping orifice 6055 in the vent system 3400 can be a particular size that is small enough to provide sufficient resistance to gas exchange but not so small as to reduce the functionality of the vent system 3400 (e.g., the ability of the movable portion 3456 of the membrane 3450 to move proximal to and away from the membrane facing surface 3424).

[0276] The actual size of each damping orifice 6055 in a particular vent system 3400 may be determined based on several factors, such as the number of damping orifices 6055, the dimensions of the damping chamber 6050 and membrane 3450, the shape and dimensions of the vent housing 3402, the shape and stiffness of the membrane 3450, and the treatment pressure. Determining the appropriate size of each damping orifice 6055 may be based on simulation, simple experimentation, and / or trial and error. The ventilation system 3400 may include multiple damping orifices 6055 to allow gas to flow into and out of the damping chamber 6050. The multiple damping orifices 6055 may together define a total cross-sectional area small enough to allow gas flow therethrough and to tolerate gas exchange between the damping chamber 6050 and the pressurized volume 6000.

[0277] As described above, the vent housing 3402 includes a plurality of protrusions 3444 configured to prevent movement of the free end of the membrane 3450 toward the membrane-facing surface 3424. The vent housing 3402 may include a plurality of protrusions 3444 and a plurality of damping orifices 6055 defined between the plurality of protrusions 3444. Gas can flow into and out of the damping chamber 6050 from the pressurized volume 6000 through the damping orifices 6055 between the protrusions 3444, and the damping orifices 6055 resist gas exchange between the damping chamber 6050 and the pressurized volume 6000 to damp vibrations of the movable portion 3456 of the membrane 3450. In these examples, small gaps are provided between the protrusions 3444 shown in FIGS. 9C-9G and 10C-10D to form the damping orifices 6055.

[0278] 5.3.4.7.2 Restrictions in the exhaust gas flow path In the example ventilation system 3400 shown in FIGS. 9A-9G, the exhaust gas flow path 6002 includes a region that has a smaller cross-sectional area than adjacent regions within the exhaust gas flow path 6002. In this example, the exhaust gas flow path 6002 includes a restriction 6006 in the exhaust gas flow path that creates a region having a smaller cross-sectional area. The cross-sectional area of ​​the exhaust gas flow path 6002 at the restriction 6006 is smaller than the cross-sectional area elsewhere within the exhaust gas flow path 6002. The membrane-facing surface 3424 may be closer to the movable portion 3456 of the membrane 3450 at the restriction 6006 (than elsewhere within the exhaust gas flow path 6002), thereby allowing the exhaust gas to pass through a smaller cross-sectional area within the exhaust gas flow path 6002.

[0279] The restriction 6006 in the exhaust gas flow path 6002 may be formed by a constriction 3425 (e.g., as described above). In the example of Figures 9A-9G, the restriction 6006 is formed by the constriction 3425 and takes the form of a contoured surface that forms a rib on the first housing member 3430. The constriction 3425 may be centrally located between the first end of the membrane 3450 and the second end of the membrane 3450.

[0280] The damping chamber 6050 may include a first end 6051 adjacent to the first end 3451 of the membrane 3450 and a second end 6052 adjacent to the second end 3452 of the membrane 3450. In the example of FIGS. 9A-9G , the restriction 6006 in the exhaust gas flow path 6002 is centrally aligned between the first end 6051 and the second end 6052 of the membrane 3450. Thus, in this example, the restriction 6006 in the exhaust gas flow path 6005 is centrally aligned between the first end 3451 of the membrane 3450 and the second end 3452 of the membrane 3450. In this example, the restriction 6006 is centrally aligned along the longitudinal length of the movable portion 3456 of the membrane 3450.

[0281] The restriction 6006 causes the region of the exhaust gas flow path 6002 to experience the lowest pressure compared to other regions of the exhaust gas flow path 6002 (due to the smallest cross-sectional area, per Bernoulli's principle). Because the pressure in the exhaust gas flow path 6002 is lowest at the restriction 6006, the force exerted on the membrane 3450 against the membrane-facing surface 3424 is greater at the restriction 6006 (than elsewhere along the length of the membrane 3450). This point of maximum force on the membrane 3450 urges the movable portion 3456 of the membrane 3450 to deform in a predictable manner. The movable portion 3456 of the membrane 3450 can predictably deflect to a greater extent along the restriction 6006 (compared to elsewhere in the exhaust gas flow path 6002). Deforming the membrane 3450 in this manner may allow the membrane 3450 to be less susceptible to vibrations along its length (compared to if the membrane 3450 were located along an exhaust gas flow path 6002 of constant cross-section and pressure along its length). Reduced vibration of the membrane 3450 may reduce the level of noise radiated from the ventilation system 3400 and may also reduce pressure fluctuations within the air circuit 4170 and / or patient interface 3000.

[0282] The vent housing 3402 may be configured such that all actual vibration of the movable portion 3456 of the membrane 3450 occurs in the first vibration mode. By centrally locating the restriction 6006 relative to the membrane 3450, it may be possible to tune the vibration of the membrane 3450 to be primarily in the first vibration mode. Although vibration of the membrane 3450 should be minimized, it may be advantageous to have all vibration of the membrane 3450 occur primarily in the first mode vibration (rather than in higher vibration modes).

[0283] 9A-9G, the damping chamber 6050 extends substantially along the entire length of the membrane 3450, with a first end 6051 of the damping chamber 6050 located adjacent the first end 3451 of the membrane 3450 and a second end 6052 of the damping chamber 6050 located adjacent the second end 3452 of the membrane 3450. An advantage of this exemplary configuration is that the first mode vibration of the membrane 3450 causes the overall volume of the damping chamber 6050 to change, forcing gas into and out of the damping chamber 6050 during vibration through the damping orifice 6055.

[0284] When the membrane 3450 is vibrated in a higher order mode, the change in volume of the damping chamber 6050 may be less significant, if at all. For example, when the membrane 3450 is vibrated in a second order mode, there may be little or no change in volume of the damping chamber 6050. The portion of the membrane 3450 between the first end 3451 of the membrane 3450 and the center point moves in one direction, while the portion of the membrane 3450 between the center point and the second end 3452 of the membrane 3450 moves in the other direction. As the volume of one half of the damping chamber 6050 increases, the volume of the other half of the damping chamber 6050 may correspondingly decrease. Gas within the damping chamber 6050 moves from one end of the damping chamber 6050 to the other, rather than being forced through the orifice 6055. In this configuration, damping effectiveness may also be reduced because less gas is forced into and out of the damping chamber 6050.

[0285] A ventilation system 3400 configured such that the membrane 3450 tends to vibrate primarily in a first-order mode may be relatively quiet, albeit noisy, due to the damping effect provided by the damping chamber 6050. In fact, some vibration damping may be achieved even when the ventilation system 3400 tolerates second or higher order vibration modes. The damping chamber 6050 in the ventilation system 3400 shown in FIGS. 10A-10D may provide a damping effect due to the first-order vibration of the membrane 3450, even if there is no restriction in the exhaust gas flow path 6002. Furthermore, a third order vibration mode may affect the volume of the damping chamber 6050, leading to a damping effect. Furthermore, even if there is no restriction in the exhaust gas flow path 6002, the damping chamber 6050 may function as a stagnant air cavity that is not significantly affected by the gas flow within the ventilation system 3400. Even when damping does not occur, the damping chamber 6050 may provide higher pressure to the membrane 3450 (as opposed to a low pressure region in the exhaust gas flow path 6002), allowing the movable part to move toward the membrane facing surface 3424 and adjust the ventilation gas flow.

[0286] 5.3.5 Decoupling Structures (Singular or Plural) In one form, the patient interface 3000 includes at least one decoupling structure (eg, a swivel or a bulb).

[0287] 5.3.6 Connection Port The connection port 3600 allows connection to the air circuit 4170 .

[0288] 5.3.7 Forehead support In one form, the patient interface 3000 includes a forehead support 3700 .

[0289] 5.3.8 Anti-asphyxiation valve In one form, the patient interface 3000 includes an anti-asphyxiation valve.

[0290] 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.

[0291] 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 4300 (e.g., any of the methods described herein, in whole or in part). 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.

[0292] 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.

[0293] 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 panel(s) 4015. The RPT device 4000 includes a chassis 4016 that supports one or more internal components of the RPT device 4000. The RPT device 4000 may include a handle 4018.

[0294] The air pressure path of the pneumatic RPT device 4000 may include one or more air path items (e.g., an inlet air filter 4112, an inlet muffler 4122, a pressure generator 4100 capable of supplying air at positive pressure (e.g., a blower 4142), an outlet muffler 4124) and one or more transducers 4270 (e.g., a pressure sensor 4272 and a flow sensor 4274).

[0295] One or more of the air path items may be disposed within a removable, unitary structure referred to 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.

[0296] The RPT device 4000 can have a power supply 4210, one or more input devices 4220, a central controller, a therapy device controller 4240, a pressure generator 4100, one or more protection circuits 4250, a memory 4260, a transducer 4270, a data communication interface 4280, and one or more output devices 4290. The electrical components 4200 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.

[0297] As noted above, in some forms of the present technology, the central controller may be configured to implement one or more algorithms 4300 expressed as a computer program stored in a non-transitory computer-readable storage medium (e.g., memory 4260). The algorithms 4300 are typically grouped into groups called modules.

[0298] An RPT device in accordance with one form of the present technology may include an air filter 4110 or multiple air filters 4110.

[0299] 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.

[0300] An RPT device in accordance with one form of the present technology may include a muffler 4120 or multiple mufflers 4120.

[0301] 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).

[0302] 5.4.1.1 Pre-processing module A pre-processing module 4310 in accordance with one form of the present technology receives as input a signal from a transducer 4270 (e.g., a flow sensor 4274 or a pressure sensor 4272) and performs one or more process steps to calculate one or more output values ​​that are used as inputs to another module (e.g., a therapy engine module 4320).

[0303] In one form of the present technology, the output values ​​include interface or mask pressure Pm, respiratory flow Qr, and leak flow Ql.

[0304] In various forms of the present technology, the pre-processing module 4310 includes one or more of the following algorithms: pressure compensation 4312, ventilation flow estimation 4314, leak flow estimation 4316, and respiratory flow estimation 4318.

[0305] 5.4.1.1.1 Pressure compensation In one form of the present technology, a pressure compensation algorithm 4312 receives as an input a signal indicative of the pressure in the pneumatic path proximal to the outlet of the pneumatic block. The pressure compensation algorithm 4312 estimates the pressure drop through the pneumatic circuit 4170 and provides as an output the estimated pressure Pm in the patient interface 3000.

[0306] 5.4.1.1.2 Estimation of ventilation flow rate In one form of the present technology, an airflow estimation algorithm 4314 receives as input an estimated pressure Pm in the patient interface 3000 and estimates the airflow Qv of air from the ventilation system 3400 in the patient interface 3000.

[0307] 5.4.1.1.3 Estimation of leakage flow rate In one form of the present technology, a leak flow estimation algorithm 4316 receives as input the total flow Qt and the ventilation flow Qv and provides as output an estimate of the leak flow Ql, hi one form, the leak flow estimation algorithm estimates the leak flow Ql by calculating the average difference between the total flow Qt and the ventilation flow Qv over a period long enough to include several respiratory cycles (e.g., about 10 seconds).

[0308] In one form, the leak flow estimation algorithm 4316 provides a leak flow Ql as an output and receives as inputs the total flow Qt, ventilation flow Qv, and estimated pressure Pm in the patient interface 3000 by calculating the leak conductance and determining the leak flow Ql as a function of the leak conductance and the pressure Pm. The leak conductance is calculated as the low-pass filtered quotient of the non-ventilated flow equal to the difference between the total flow Qt and the ventilation flow Qv and the low-pass filtered square root of the pressure Pm, with the low-pass filter time constant having a value sufficient to include several respiratory cycles (e.g., about 10 seconds). The leak flow Ql may be estimated as a function of the product of the leak conductance and the pressure Pm.

[0309] 5.4.1.1.4 Respiratory flow estimation In one form of the present technology, the respiratory flow estimation algorithm 4318 receives as inputs the total flow Qt, the ventilation flow Qv and the leak flow Ql and estimates the respiratory flow Qr of air to the patient by subtracting the ventilation flow Qv and the leak flow Ql from the total flow Qt.

[0310] 5.4.1.2 Treatment Engine Module In one form of the present technology, the therapy engine module 4320 receives as inputs one or more of the pressure in the patient interface 3000, Pm, and the respiratory flow of air to the patient, Qr, and provides one or more therapy parameters as outputs.

[0311] 5.4.1.3 Treatment Control Module The treatment control module 4330 according to one aspect of the present technology receives treatment parameters from the treatment parameter determination algorithm 4329 of the treatment engine module 4320 as input and controls the pressure generator 4100 to deliver airflow according to these treatment parameters.

[0312] In one form of the present technology, the treatment parameter is a treatment pressure Pt, and the treatment control module 4330 controls the pressure generator 4100 to deliver an airflow from the pressure generator 4100 such that the mask pressure Pm at the patient interface 3000 is equal to the treatment pressure Pt.

[0313] 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).

[0314] 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.

[0315] 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.

[0316] FIG. 13 illustrates various configurations for employing an exemplary ventilation system 3400 with various patient interfaces 3000A-C.

[0317] An interface provided by the first housing member 3430 of the vent housing 3402 connects the vent system 3400 to the air circuit connector 4171, joining the vent system 3400 with the air circuit 4170 and placing the vent system 3400 in the flow path. In this example, an inlet connection 3416 of the first housing member 3430 allows fluid communication between the vent housing 3402 and the air circuit 4170.

[0318] The second housing member 3440 of the vent housing 3402 may provide an interface for connecting the vent system 3400 to a vent connector tube 4180 at a tube connector 4182. The vent connector tube 4180 is known as a short length of tube. In this example, the outlet connection 3420 of the second housing member 3440 is configured to fluidly connect the vent housing 3402 to the vent connector tube elbow 4181.

[0319] The ventilation connector tube 4180 may be connected to the nasal patient interface 3000A or the nasal pillows patient interface 3000B. The nasal patient interface 3000A may be configured to seal around at least the underside of the patient's nose, or may be configured to receive at least the tip of the patient's nose and seal around the nasal area. The nasal pillows patient interface 3000B may include pillows on the stems for sealing with each nostril via the ventilation connector tube elbows 4181 opposite the tubing connectors 4182. The ventilation connector tube 4180 may be lighter and / or have a smaller diameter than the air circuit 4170 because such a configuration allows the ventilation system 3400 to be spaced apart from the patient interface 3000A / 3000B (to reduce tubing drag). In the case of the full face patient interface 3000C, which may be configured to seal against the patient's face around both the nose and mouth and direct gas to the patient's nose and mouth through a single opening, or may be configured as a miniature full face patient interface with one or two openings to direct gas to the patient's nares and another opening to direct gas to the patient's mouth, the vent connector tube 4180 may be omitted and the outer wall of the vent housing 3402 may be joined to the decoupling structure 3500.

[0320] In either of these configurations, a heat and moisture exchanger (HMX) (not shown) may also be provided. For example, an HMX may be provided between the patient interface 3000 and the ventilation connector tubing 4180 or between the tubing connector 4182 and the ventilation system 3400. Alternatively, the HMX may be located within the plenum chamber 3200. In either of these HMX configurations, placing the HMX between the patient's airway and the ventilation system 3400 may allow heat and moisture from the exhaled air to be transferred to the HMX material before the exhaled air is vented to the atmosphere.

[0321] 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 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.

[0322] 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.

[0323] 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 airflow. 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).

[0324] 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.

[0325] According to one form, the reservoir 5110 may be laterally removable from the humidifier 5000, for example as shown in Figures 5A and 5B.

[0326] 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.

[0327] 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.

[0328] 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).

[0329] 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)).

[0330] 5.7 Respiratory waveform Figure 6 shows a typical respiratory waveform for a sleeping human model. 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; inhalation time, Ti, 1.6 seconds; peak inspiratory flow, Qpeak, 0.4 L / sec; exhalation 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%.

[0331] 5.8 Screening, Diagnostic, and Monitoring Systems 5.8.1 Polysomnography 7A shows a patient 1000 undergoing polysomnography (PSG). The PSG system includes a headbox 2000. The headbox 2000 receives and records signals from the following sensors: EOG electrodes 2015, EEG electrodes 2020, ECG electrodes 2025, submental EMG electrodes 2030, a snoring sensor 2035, a respiratory inductance plethysmogram (respiratory effort sensor) 2040 on a chest cuff, a respiratory inductance plethysmogram (respiratory effort sensor) 2045 on an abdominal cuff, an oronasal cannula with oral thermistor 2050, a photoplethysmograph (pulse oximeter) 2055, and a body position sensor 2060. The electrical signal is referred to the ground electrode (ISOG) 2010, which is positioned at the center of the forehead.

[0332] 5.8.2 Non-obstructive monitoring systems An example of a monitoring device 7100 for monitoring the respiration of a sleeping patient 1000 is shown in Figure 7B. The monitoring device 7100 includes a non-contact motion sensor directed primarily towards the patient 1000. The motion sensor is configured to generate one or more signals indicative of the body movements of the patient 1000. From these signals, a signal indicative of the patient's respiratory movements can be derived.

[0333] 5.9 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.

[0334] 5.9.1 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).

[0335] 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.

[0336] 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). Such ambient humidity may differ from the humidity outside the room where the patient is sleeping.

[0337] In another example, the ambient pressure may be the pressure immediately surrounding or external to the body.

[0338] 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.

[0339] Automatic Positive Airway Pressure (APAP) Therapy: 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.

[0340] 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).

[0341] 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."

[0342] 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.

[0343] 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.

[0344] 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.

[0345] Noise Conduction (Acoustic): In this document, conducted noise refers to noise that is carried to the patient by the pneumatic pathway (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.

[0346] 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.

[0347] 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).

[0348] Patient: A person with or without a respiratory disease.

[0349] Pressure: Force per unit area. Pressure can be expressed 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.

[0350] 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.

[0351] Respiratory Pressure Therapy (RPT): The application to the airway entrance of an air supply at therapeutic pressure, typically positive pressure relative to atmosphere.

[0352] Ventilator: A mechanical device that provides pressure support to a patient while they perform some or all of the work of breathing.

[0353] 5.9.1.1 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 (in a family of products sold under this registered 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.

[0354] Polycarbonate: A thermoplastic polymer of bisphenol A carbonate.

[0355] 5.9.1.2 Mechanical properties Elasticity: The ability of a material to absorb energy during elastic deformation and to release the energy when unloaded.

[0356] Elastic: Releases substantially all of the energy upon unloading. Examples include certain silicone and thermoplastic elastomers.

[0357] 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.

[0358] 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.

[0359] 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.

[0360] 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 airway entrance under a pressure load of, for example, approximately 20-30 cmH2O.

[0361] 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.

[0362] 5.9.2 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.

[0363] Respiratory rate: The patient's spontaneous breathing rate, usually measured in breaths per minute.

[0364] Duty cycle: The ratio of inspiration time Ti to total breathing time Ttot.

[0365] Exercise (Respiration): Respiratory effort is said to refer to the movement made by the spontaneous breathing of a person trying to breathe.

[0366] Expiratory portion of the respiratory cycle: the period from the start of expiratory flow to the start of inspiratory flow.

[0367] 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. 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.

[0368] 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.

[0369] 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.

[0370] Hyperventilation: An increase in flow to a level higher than normal.

[0371] 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.

[0372] 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).

[0373] Positive end-expiratory pressure (PEEP): The pressure above atmosphere in the lungs that exists at the end of expiration.

[0374] Peak flow (Qpeak): The maximum value of flow during the inspiratory portion of the respiratory flow waveform.

[0375] 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.

[0376] Tidal volume (Vt): The volume of air inhaled or exhaled during normal breathing without extra effort. In principle, the inhaled volume Vi (volume of air inhaled) is equal to the exhaled volume Ve (volume of air exhaled), so a single tidal volume Vt can be defined as equal to either volume. In practice, the tidal volume Vt is estimated as some combination (e.g., the average of the inhaled volume Vi and the exhaled volume Ve).

[0377] (Inspiration) Time (Ti): The duration of the inspiratory portion of the respiratory flow waveform.

[0378] (Expiratory) Time (Te): The duration of the expiratory portion of the respiratory flow waveform.

[0379] (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.

[0380] 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).

[0381] 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).

[0382] 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.

[0383] 5.9.3 Anatomy 5.9.3.1 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.

[0384] Larynx: The larynx or voice box that houses the vocal cords and connects the lower part of the pharynx (hypopharynx) to the trachea.

[0385] 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.

[0386] 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.

[0387] 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).

[0388] 5.9.4 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.

[0389] Elbow: 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.

[0390] 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.

[0391] 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).

[0392] Membrane: Membrane is taken to mean a typically thin-walled element, preferably substantially non-resistant to bending and resistant to stretching.

[0393] 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.

[0394] 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.

[0395] 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.

[0396] Stiffener: A stiffener is taken to mean a structural component designed to increase the bending resistance of another component in at least one direction.

[0397] Strut: A strut is taken to mean a structural component designed to increase the compressive resistance of another component in at least one direction.

[0398] 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.

[0399] Tie (noun): A structure designed to resist tension.

[0400] Vent: (noun): A structure that allows airflow to 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.

[0401] 5.10 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.

[0402] 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.

[0403] 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.

[0404] 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.

[0405] 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.

[0406] 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.

[0407] 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.

[0408] 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.

[0409] 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.

[0410] Although the technology herein has been described with reference to particular 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 may be changed and / or aspects may occur simultaneously or even synchronously. Thus, it should be understood that numerous modifications are possible in the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the technology. [Explanation of symbols]

[0411] 1000 patients 1100 Bedmate 3000 Patient Interface 3100 Seal forming structure 3200 Plenum Chamber 3300 Positioning and Stabilizing Structures 3400 Ventilation System 3402 Ventilated Housing 3404 First end of vent housing 3405 Second end of vent housing 3406 Longitudinal axis of vent housing 3407 Entrance 3408 Exit 3416 Inlet connection 3418 Bayonet attachment 3420 Outlet Connection 3422 Internal Channel 3424 Membrane facing surface 3425 Constriction section 3430 first housing member 3431 first end of first housing member 3432 second end of first housing member 3433 Round surface 3434 Shaft 3435 flange 3436 Flange protrusion 3437 Diffuser Retaining Rim 3438 Second housing member connection 3440 second housing member 3441 first end of second housing member 3442 second end of second housing member 3444 Protrusion 3446 Membrane Stop Flange 3448 Diffuser holder 3450 Membrane 3451 First end of membrane 3452 Second end of membrane 3454 longitudinal axis of membrane 3456 Movable membrane 3460 Membrane support part 3462 Connection 3464 Membrane support flange 3465 Baffle section 3466 First end of baffle section 3467 Second end of baffle section 3468 Baffle flange 3470 Exhaust gas orifice member 3471 Diffusion type exhaust gas orifice 3472 Non-diffusion type exhaust gas orifice 3473 Common Exhaust Gas Orifice 3474 Diffuser parts 3475 Intermediate Exhaust Gas Flow Orifice 3476 First end of exhaust gas orifice member 3477 Second end of exhaust gas orifice member 3478 Intermediate exhaust gas orifice 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 4100 Pressure Generator 4110 Air Filter 4112 Inlet Air Filter 4114 Outlet air filter 4120 Muffler 4122 Inlet muffler 4124 Exit muffler 4142 Blower 4144 Motor 4160 Anti-spillback valve 4170 Air Circuit 4171 Air Circuit Connector 4180 Ventilated Connector Pipe 4181 Ventilated Connector Pipe Elbow 4182 Pipe Connector 4200 Electrical Components 4202 Printed Circuit Board Assembly (PCBA) 4210 Electrical power supply 4220 input devices 4240 Therapy Device Controller 4250 protection circuit 4260 memory 4270 Converter 4272 Pressure Sensor 4274 Flow Sensor 4280 data communications interface 4290 output device 4300 Algorithm 4310 Pre-processing Module 4312 Pressure Compensation 4314 Ventilation flow rate estimation 4316 Leakage flow rate estimation 4318 Respiratory flow estimation 4320 Treatment Engine Module 4330 Treatment Control Module 4329 Treatment parameter determination algorithm 5000 humidifier 5002 Humidifier inlet 5004 Humidifier outlet 5006 Humidifier Base 5110 Humidifier Reservoir 5120 Conductive parts 5130 Humidifier Reservoir Dock 5135 Lock lever 5150 Water Level Indicator 5240 heating element 6000 pressurized volume 6002 Exhaust gas flow path 6004 Exhaust gas flow path inlet 6006 Restricted Section 6040 Stagnant Air Cavity 6050 damping chamber 6051 First end of damping chamber 6052 Second end of damping chamber 6055 Damping Orifice 6100 Atmosphere 6201 Gas flow from RPT device 6202 Therapeutic gas flow 6203 Ventilation gas flow 6204 Diffusion ventilation gas flow 6205 Non-diffusive ventilation gas flow 6206 Decay Chamber Gas Flow

Claims

1. A patient interface comprising: When in use, at least 6 cmH above ambient air pressure throughout the patient's breathing cycle ２ a plenum chamber at least partially defining a volume pressurizable to a therapeutic pressure of O, said plenum chamber including a plenum chamber inlet port sized and configured to receive a therapeutic gas flow for breathing by a patient; a seal-forming structure constructed and arranged to seal against an area of ​​the patient's face surrounding an entrance to the patient's airways, said seal-forming structure having holes therein whereby said therapeutic gas flow is delivered to at least an entrance to the patient's nares in use, said seal-forming structure constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient's respiratory cycle in use; a positioning and stabilizing structure configured to hold the seal-forming structure in a therapeutically effective position on the patient's head; a venting structure configured to continuously discharge the ventilated gas flow to atmosphere throughout the patient's respiratory cycle, said venting structure comprising: a vent housing including an inlet configured to receive a gas flow from a respiratory pressure therapy device, an outlet configured to provide a therapeutic gas flow to the plenum chamber inlet port, and at least one exhaust gas orifice configured to release a ventilation gas flow to the atmosphere, the at least one exhaust gas orifice being sized and shaped to maintain a therapeutic pressure in the plenum chamber in use; a membrane disposed within the vent housing, the membrane having a first end and a second end spaced apart along a longitudinal axis of the membrane, the membrane having a movable portion disposed between the first end of the membrane and the second end of the membrane and surrounding the longitudinal axis; the movable portion of the membrane is spaced radially from a membrane-facing surface inside the vent housing relative to a longitudinal axis of the membrane to define an exhaust gas flow path between the movable portion of the membrane and the membrane-facing surface, the exhaust gas flow path being configured, in use, to allow gas from the volume to flow through the exhaust gas flow path and through at least one exhaust gas orifice to atmosphere; A patient interface wherein the movable portion of the membrane is elastically deformable and configured to move radially relative to the membrane facing surface in response to a pressure differential between the inside and outside of the membrane, thereby varying the cross-sectional area of ​​the exhaust gas flow path and regulating ventilation gas flow throughout a therapeutic pressure range.

2. The patient interface of claim 1 , wherein the movable portion of the membrane is substantially cylindrical or frustoconical.

3. 3. The patient interface of claim 1, wherein the vent housing includes a first end and a second end aligned along a longitudinal axis of the vent housing, and wherein the longitudinal axis of the membrane is aligned with the longitudinal axis of the vent housing.

4. 4. The patient interface of claim 3, wherein the movable portion of the membrane includes one or more walls aligned parallel to gas flow through the vent housing from a first end of the vent housing to a second end of the vent housing.

5. 5. A patient interface according to claim 3 or 4, wherein the vent housing includes a first housing member at a first end of the vent housing and a second housing member at a second end of the vent housing, the first housing member and the second housing member being configured to be connected together.

6. The patient interface of claim 5 , wherein the first housing member includes an inlet connection configured to fluidly connect the vent structure to a supply conduit.

7. 7. A patient interface according to claim 5 or 6, wherein the second housing member includes an outlet connection configured to fluidly connect the vent structure to the patient interface or to a tube configured to be connected to the patient interface.

8. A patient interface according to any preceding claim, wherein the membrane is joined at a first end of the membrane to a membrane support.

9. A patient interface according to any preceding claim, wherein the movable portion of the membrane is formed from silicone rubber.

10. 10. A patient interface according to any one of claims 1 to 9, comprising a damping structure configured to damp vibrations of the movable portion of the membrane, the damping structure being disposed between a wall of the vent housing and the movable portion of the membrane, the damping structure containing a gas.

11. 11. A patient interface according to claim 10, wherein the damping structure includes a damping chamber within the venting housing configured to damp vibrations of the movable portion of the membrane, the damping chamber being disposed between the wall of the venting housing and the movable portion of the membrane and containing the gas.

12. 12. A patient interface according to claim 11, wherein the vent housing at least partially defines the damping chamber.

13. 13. A patient interface according to claim 11 or 12, wherein one of the inner and outer sides of the membrane faces the membrane facing surface, and the other of the inner and outer sides of the membrane at least partially defines the damping chamber.

14. A patient interface according to any one of claims 11 to 13, wherein the dampening chamber, in use, is in fluid communication with a pressurised volume containing the gas.

15. A patient interface according to any one of claims 11 to 14, wherein the membrane and the damping chamber are configured such that movement of the movable part of the membrane causes the volume of the damping chamber to increase or decrease.

16. 16. A patient interface according to claim 15, wherein the vent housing and damping chamber are configured to damp vibrations of the movable portion of the membrane by restricting gas exchange between the damping chamber and a pressurized volume containing the gas.

17. 17. A patient interface according to any preceding claim, wherein the exhaust gas flow path includes a restricted region including a first region having a first cross-sectional area and a second region having a second cross-sectional area that is smaller than the first cross-sectional area.

18. 18. The patient interface of claim 17, wherein the membrane facing surface defining the second region of the exhaust gas flow path is closer to the membrane than the membrane facing surface defining the first region of the exhaust gas flow path.

19. 20. The patient interface of claim 18, wherein the membrane facing surface is closest to the movable portion of the membrane at the location of the restriction region.

20. 20. A patient interface according to claim 18 or 19, wherein the membrane facing surface includes a restriction that forms the restricted area in the exhaust gas flow path.

21. 21. A patient interface according to claim 20, wherein the membrane facing surface includes a contoured surface that forms the restriction.

22. 22. A patient interface according to claim 20 or 21, wherein the restriction comprises a rib in the membrane-facing surface.

23. A patient interface according to any one of claims 20 to 22, wherein the restriction portion is centrally located between the first end of the membrane and the second end of the membrane.

24. 24. A patient interface according to any one of claims 20 to 23, comprising a damping chamber within the vent housing configured to damp vibrations of a movable portion of the membrane, the damping chamber being disposed between a wall of the vent housing and the movable portion of the membrane and containing a gas, the damping chamber including a first end adjacent to a first end of the membrane and a second end adjacent to a second end of the membrane, the restricted area in the exhaust gas flow path being centrally aligned between the first end of the damping chamber and the second end of the damping chamber.

25. 25. A patient interface according to any one of claims 1 to 24, wherein a damping structure containing gas disposed between a wall of the vent housing and the movable portion of the membrane is configured to reduce vibrations of the movable portion of the membrane at vibration modes higher than a primary vibration mode.

26. 26. A patient interface according to any one of claims 1 to 25, wherein the vent housing has a portion that extends towards the vent housing inlet, the portion of the vent housing that extends towards the vent housing inlet configured to limit movement of the movable part of the membrane towards the membrane facing surface.

27. 27. A patient interface according to claim 26, wherein the portion of the vent housing that extends towards the vent housing inlet is configured to contact an end of the membrane that is not facing the membrane facing surface to prevent the end of the membrane from moving towards the membrane facing surface.

28. 28. A patient interface according to claim 27, wherein the vent housing includes at least one protrusion configured to contact the end of the membrane and limit movement of the end of the membrane, the protrusion protruding toward the inlet of the vent housing.

29. 30. A patient interface according to claim 28, wherein the at least one protrusion is external to the exhaust gas flow path.

30. 30. A patient interface as described in claim 28 or 29, wherein the vent housing includes a plurality of protrusions protruding toward the inlet of the vent housing and a plurality of damping orifices between the protrusions, the damping orifices providing passageways to allow gas to flow from a pressurized volume containing gas into and out of the damping chamber, the damping orifices resisting gas exchange between the damping chamber and the pressurized volume to damp vibrations of the movable portion of the membrane.

31. 31. A patient interface according to any one of claims 1 to 30, wherein the vent housing includes a rounded surface at or adjacent an inlet to the exhaust gas flow path that facilitates redirection of vent gas flow adjacent the inlet to the exhaust gas flow path, the rounded surface formed on the membrane facing surface.

32. 32. A patient interface according to any preceding claim, wherein the vent housing allows exhaust gas transfer to atmosphere and includes a plurality of diffused exhaust gas orifices arranged around a periphery of the vent housing.

33. 33. A patient interface according to claim 32, wherein the vent housing includes at least one diffused exhaust gas orifice disposed around a periphery of the vent housing to allow exhaust gas transfer to atmosphere, and at least one non-diffused exhaust gas orifice disposed around a periphery of the vent housing to allow exhaust gas transfer to atmosphere.

34. 34. A patient interface according to claim 33, wherein the diffused exhaust gas orifice is located at or near a first end of the vent housing and the non-diffused exhaust gas orifice is centrally located between the first end of the vent housing and the second end of the vent housing.

35. 35. A patient interface according to claim 33 or 34, wherein the at least one diffused exhaust gas orifice opens in a lateral direction and the at least one non-diffused exhaust gas orifice opens partially towards the second end of the vent housing in a direction oblique to the lateral direction.

36. 36. A patient interface according to any one of claims 33 to 35, comprising a diffuser member configured to, in use, diffuse and / or muffle gases contacting the diffuser member, the diffuser member being arranged in series with the at least one diffusion-type exhaust gas orifice.

37. 37. A patient interface according to any one of claims 33 to 36, wherein the vent structure is configured to allow gas flow through the at least one non-diffused exhaust gas orifice when gas cannot pass through the at least one diffused exhaust gas orifice.

38. 38. A patient interface according to claim 37, wherein the vent structure is shaped to require more gas flow redirection through the at least one non-diffused exhaust gas orifice than through the diffused exhaust gas orifice.

39. 39. A patient interface according to any one of claims 33 to 38, comprising an exhaust gas orifice member defining the at least one exhaust gas orifice, the exhaust gas orifice member configured to connect to a first housing member of the vent housing and disposed on a periphery of the vent housing, the diffused exhaust gas orifice and the non-diffused exhaust gas orifice defined in the exhaust gas orifice member.

40. 40. A patient interface as described in claim 39, wherein the at least one diffusional exhaust gas orifice is located at or near a first end of the exhaust gas orifice member and the at least one non-diffusional exhaust gas orifice is located at or near a second end of the exhaust gas orifice member opposite the first end of the exhaust gas orifice member.

41. 41. A patient interface according to claim 39 or 40, wherein a diffuser member is contained between the exhaust gas orifice member and the first housing member and is retained in a vent structure by the exhaust gas orifice member.

42. A patient interface according to any preceding claim, wherein the movable part of the membrane is positioned relative to the longitudinal axis of the membrane radially outward from the membrane facing surface.

43. A patient interface according to any preceding claim, wherein the movable portion of the membrane is configured to contract and move radially inwards towards a membrane facing surface.

44. 44. A patient interface according to any one of claims 1 to 43, wherein the membrane-facing surface is provided on an outer surface of a first housing member of the vent housing that defines the inlet of the vent housing and extends within the membrane towards the outlet of the vent housing, the outer surface being disposed within the membrane.

45. 45. A patient interface as described in claim 44, wherein the first housing member includes a shaft configured to protrude into the interior of the vent structure from a first end of the first housing member that defines the inlet of the vent housing, and the membrane facing surface is provided on an outer surface of the shaft at or near a second end opposite the first end of the first housing member in the extension direction of the shaft.

46. 46. ​​A patient interface according to claim 45, wherein the first housing member includes an axially rounded surface at the second end of the first housing member at or near an entrance to an exhaust gas flow path.

47. A patient interface according to any preceding claim, wherein the exhaust gas flow path is formed circumferentially within the ventilation housing.

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