Humidification with HME and heated air delivery pipe

Abstract

A CPAP system for providing positive pressure air for respiratory therapy to a patient includes an RPT device configured to provide a flow of air at a therapy pressure, a patient interface forming a plenum pressurizable to the therapy pressure, an air delivery tube configured to deliver the flow of air at the therapy pressure from the RPT device to the patient interface, and an air delivery tube configured to deliver the flow of air at the therapy pressure from the RPT device to the patient interface. A system and method for humidifying an exhaled air flow of a patient, a heat and humidity exchanger (HME) constructed and arranged for retaining moisture from the exhaled air flow of the patient, where the retained moisture from the HME is returned into the air flow for humidification, a controllable heater configured and arranged for heating the HME and / or heating air entering the HME, and a controller configured and arranged for controlling the humidity of the air flow. And a controller configured to regulate heating of the controllable heater to regulate moisture returned from the HME to the airflow for humidification.

Description

[0001] A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 1 Cross-reference to related applications

[0003] This application is a divisional application of the patent application with application number 201980082591.2, application date November 13, 2019, and invention name “Humidification with HME and heated air delivery tube”, and the patent application with application number 201980082591.2 is the Chinese national phase application of the international application PCT / IB2019 / 059741 filed on November 13, 2019, which claims the benefit of U.S. Provisional Application No. 62 / 767,149 filed on November 14, 2018, which is incorporated herein by reference in its entirety. 2 Technical Background 2.1 Technical Field

[0004] The present technology relates to one or more of the screening, diagnosis, monitoring, treatment, prevention and improvement of breathing-related disorders. The present technology also relates to medical devices or equipment and their uses.

[0005] 2.2 Description of related technologies

[0006] 2.2.1 Human respiratory system and its disorders

[0007] The human respiratory system facilitates gas exchange. The nose and mouth form the entrance to the patient's airway.

[0008] The airway includes a series of branching tracheae, which become narrower, shorter and more numerous as they penetrate deeper into the lungs. The main function of the lungs is gas exchange, allowing oxygen to enter the venous blood from the inhaled air and expel carbon dioxide from the opposite direction. The trachea is divided into the left main bronchi and the right main bronchi, which are eventually divided into terminal bronchioles. The bronchi constitute the conducting airways, but do not participate in gas exchange. Further branches of the airway lead to the respiratory bronchioles and eventually to the alveoli. The alveolar region of the lungs is the area where gas exchange occurs and is called the respiratory zone. See "Respiratory Physiology", 9th edition, published by John B.West, Lippincott Williams & Wilkins in 2012.

[0009] There is a range of breathing disorders. Some disorders can be characterised by specific events such as apnea, hypopnea and hyperpnea.

[0010] Examples of breathing disorders include obstructive sleep apnea (OSA), Cheyne-Stokes Respiration (CSR), respiratory insufficiency, obesity hyperventilation syndrome (OHS), chronic obstructive pulmonary disease (COPD), neuromuscular disease (NMD), and chest wall disease.

[0011] Obstructive Sleep Apnea (OSA) is a form of sleep disordered breathing (SDB) characterized by events including occlusion or obstruction of the upper airway during sleep. It results from a combination of an abnormally small upper airway and normal loss of muscle tone in the area of ​​the tongue, soft palate, and posterior oropharyngeal wall during sleep. The condition causes affected patients to stop breathing, typically for periods of 30 to 120 seconds, sometimes 200 to 300 times per night. This often leads to excessive daytime sleepiness and can lead to cardiovascular disease and brain damage. Complications are common disorders, especially in middle-aged overweight men, but those affected may not be aware of the problem. See U.S. Patent No. 4,944,310 (Sullivan).

[0012] Cheyne-Stokes respiration (CSR) is another form of sleep-disordered breathing. CSR is a disorder of the patient's respiratory controller in which there are rhythmic alternating cycles of boom-and-bust ventilation called CSR cycles. CSR is characterized by repeated hypoxia and reoxygenation of arterial blood. CSR can be harmful because of the repeated lack of oxygen. In some patients, CSR is associated with repeated arousals from sleep, which leads to severe sleep disruption, increased sympathetic activity, and increased afterload. See U.S. Patent No. 6,532,959 (Berthon-Jones).

[0013] Respiratory failure is an umbrella term for breathing disorders in which the lungs cannot take in enough oxygen or exhale enough CO2 to meet the patient's needs. Respiratory failure may include some or all of the following disorders.

[0014] Patients with respiratory insufficiency, a form of respiratory failure, may experience abnormal shortness of breath during exercise.

[0015] Obesity Hyperventilation Syndrome (OHS) is defined as the combination of severe obesity and chronic hypercapnia during wakefulness in the absence of other known causes of hypoventilation. Symptoms include dyspnea, morning headache, and excessive daytime sleepiness.

[0016] Chronic obstructive pulmonary disease (COPD) includes any of a group of lower airway diseases that have certain common features. These diseases include increased resistance to air flow, prolonged expiratory phase of breathing, and loss of normal elasticity of the lungs. Examples of COPD are emphysema and chronic bronchitis. COPD is caused by chronic smoking (a major risk factor), occupational exposure, air pollution, and genetic factors. Symptoms include: dyspnea on exertion, chronic cough, and sputum production.

[0017] Neuromuscular disease (NMD) is a broad term that covers many diseases and disorders that impair muscle function directly through intrinsic muscle pathology or indirectly through neuropathology. Some NMD patients are characterized by progressive muscle damage, which leads to loss of walking ability, wheelchair use, dysphagia, respiratory muscle weakness, and ultimately death from respiratory failure. Neuromuscular disorders can be divided into rapidly progressive and slowly progressive: (i) rapidly progressive disorders: characterized by muscle damage over several months and leading to death within a few years (e.g., juvenile amyotrophic lateral sclerosis (ALS) and Duchenne muscular dystrophy (DMD)); (ii) variable or slowly progressive diseases: characterized by worsening muscle damage over several years and only slightly shortening life expectancy (e.g., limb-girdle muscular dystrophy, facioscapulohumeral muscular dystrophy and myotonic dystrophy). Symptoms of respiratory failure in NMD include increasing general weakness, difficulty swallowing, dyspnea during exertion and at rest, fatigue, lethargy, morning headaches, and difficulty concentrating and mood changes.

[0018] Chest wall disorders are a group of chest deformities that result in inefficient connections between the respiratory muscles and the thorax. These disorders are usually characterized by restrictive defects and have the potential for long-term hypercapnic respiratory failure. Scoliosis and / or kyphoscoliosis can cause severe respiratory failure. Symptoms of respiratory failure include: dyspnea during exertion, peripheral edema, orthopnea, recurrent chest infections, morning headaches, fatigue, poor sleep quality, and loss of appetite.

[0019] A range of treatments have been used to treat or improve such conditions. In addition, such treatments can be used to prevent breathing disorders in otherwise healthy individuals. However, these treatments have a number of disadvantages.

[0020] 2.2.2 Treatment

[0021] Various therapies, such as continuous positive airway pressure (CPAP) therapy, non-invasive ventilation (NIV), and invasive ventilation (IV) have been used to treat one or more of the above-mentioned respiratory diseases.

[0022] Continuous Positive Airway Pressure (CPAP) therapy has been used to treat obstructive sleep apnea (OSA). The mechanism of action is that the continuous positive airway pressure acts as a pneumatic splint and can prevent upper airway occlusion, such as by pushing the soft palate and tongue forward and away from the posterior oropharyngeal wall. Treatment of OSA treated by CPAP can be voluntary, so if the patient finds the device used to provide such treatment to be any one or more of: uncomfortable, difficult to use, expensive, and unsightly, the patient may choose not to comply with the treatment.

[0023] Non-invasive ventilation (NIV) provides ventilation support to patients through the upper airway to help them breathe and / or maintain appropriate oxygen levels in the body by completing some or all of the work of breathing. Ventilatory support is provided via a non-invasive patient interface. NIV has been used to treat CSR and respiratory failure in the form of OHS, COPD, NMD, and chest wall disease. In some forms, the comfort and effectiveness of these treatments can be improved.

[0024] Non-invasive ventilation (IV) provides ventilation support to patients who are unable to breathe effectively on their own and can be provided using a tracheostomy tube. In some forms, the comfort and effectiveness of these treatments can be improved.

[0025] 2.2.3 Treatment system

[0026] These treatments can be provided by a therapeutic system or device.Such systems and devices can also be used to screen, diagnose or monitor a condition without treating the condition.

[0027] The therapy system may include a respiratory pressure therapy device (RPT device), air circuit, humidifier, patient interface, and data management.

[0028] Another form of treatment system is a mandibular repositioning device.

[0029] 2.2.3.1 Patient interface

[0030] The patient interface can be used to engage the respiratory apparatus to its wearer, for example by providing an air flow to the entrance of the airway. The air flow can be provided to the patient's nose and / or mouth via a mask, to the mouth via a tube, or to the patient's trachea via a tracheostomy tube. Depending on the treatment to be applied, the patient interface can form a seal with an area such as the patient's face, thereby causing gas to be delivered at a pressure that is sufficiently different from the ambient pressure (e.g., a positive pressure of approximately 10 cmH2O relative to the ambient pressure) to achieve the treatment. For other forms of treatment, such as oxygen delivery, the patient interface may not include a seal sufficient to deliver gas at a positive pressure of approximately 10 cmH2O to the airway.

[0031] Certain other mask systems may not be functionally suitable for use in this field. For example, a purely decorative mask may not be able to maintain a suitable pressure. Masks used for underwater swimming or diving may be configured to prevent water from flowing in from an external high pressure, rather than maintaining air at a higher pressure than the environment inside.

[0032] Certain masks may be clinically disadvantageous to the present technology, for example where they block airflow through the nose and only allow it through the mouth.

[0033] Certain masks may be uncomfortable or impractical for the present technology if they require the patient to insert a portion of the mask structure into their mouth to form and maintain a seal with their lips.

[0034] Certain masks may not be feasible for use while sleeping, such as when sleeping on one's side in bed with the head on a pillow.

[0035] The design of a patient interface presents several challenges. The face has a complex three-dimensional shape. The size and shape of the nose and head vary significantly from person to person. Because the head is composed of bone, cartilage, and soft tissue, different areas of the face react differently to mechanical forces. The jaw or mandible can move relative to other bones of the skull. The entire head can move during a respiratory therapy session.

[0036] Due to these challenges, some masks face one or more of the following problems: obtrusive, unsightly, expensive, disproportionate, difficult to use, and uncomfortable, especially when worn for long periods of time or when the patient is not familiar with the system. Wrongly sized masks can cause reduced compliance, reduced comfort, and unfavorable patient outcomes. Masks designed only for pilots, masks designed to be part of personal protective equipment (e.g., filtering masks), SCUBA masks, or masks designed to apply anesthetics are acceptable for their original purposes, but for long periods of time (e.g., several hours), such masks are not as comfortable as ideal. This discomfort may lead to reduced patient compliance with therapy. This is even more true if the mask is worn during sleep.

[0037] CPAP therapy is very effective in treating certain breathing disorders, assuming the patient complies with the therapy. If the mask is uncomfortable or difficult to use, the patient may not comply with the therapy. Since patients are often advised to wash their masks regularly, if the mask is difficult to clean (e.g., difficult to assemble or disassemble), the patient may not wash their mask, which may affect patient compliance.

[0038] While masks used in other applications (eg, pilots) may not be suitable for treating sleep disordered breathing, masks designed for treating sleep disordered breathing may be suitable for other applications.

[0039] For these reasons, a diverse field of patient interfaces for delivering CPAP during sleep has emerged.

[0040] 2.2.3.1.1 Sealing structure

[0041] The patient interface may include a seal-forming structure. Since it is in direct contact with the patient's face, the shape and configuration of the seal-forming structure may directly affect the effectiveness and comfort of the patient interface.

[0042] The patient interface is characterized in part according to the design intent of the seal-forming structure to engage with the face when in use. In one form of the patient interface, the seal-forming structure may include a first sub-portion and a second sub-portion, the first sub-portion forming a seal around the left nostril and the second sub-portion forming a seal around the right nostril. In one form of the patient interface, the seal-forming structure may include a single element that surrounds both nostrils when in use. Such a single element may be designed to, for example, cover the upper lip area and the bridge of the nose area of ​​the face. In one form of the patient interface, the seal-forming structure may include an element that surrounds the mouth area when in use, for example, by forming a seal on the lower lip area of ​​the face. In one form of the patient interface, the seal-forming structure may include a single element that surrounds both nostrils and the mouth area when in use. These different types of patient interfaces may be given various names by their manufacturers, including nasal masks, full-face masks, nasal pillows, nasal sprays, and oronasal masks.

[0043] A seal-forming structure that is effective in one area of ​​a patient's face may not be suitable in another area, for example, because of the different shapes, structures, variations, and sensitive areas of the patient's face. For example, a seal on swimming goggles that covers the patient's forehead may not be suitable for use on the patient's nose.

[0044] Certain seal-forming structures may be designed for mass manufacturing so that one design is appropriate, 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 a mass-manufactured patient interface, one or both must adapt to form a seal.

[0045] One type of seal-forming structure extends around the periphery of the patient interface and is used to seal against the patient's face when a force is applied to the patient interface while the seal-forming structure is in facing engagement with the patient's face. The seal-forming structure may include an air or fluid filled cushion, or a molded or formed surface of a resilient sealing element made of an elastomer (e.g., rubber). With this type of seal-forming structure, if the fit is inadequate, there will be a gap between the seal-forming portion and the face, and additional force will be required to force the patient interface against the face to achieve a seal.

[0046] Another type of seal-forming structure includes a flap seal of thin material positioned around the perimeter of the mask to provide a self-sealing action against the patient's face when positive pressure is applied within the mask. Similar to the previous forms of seal-forming portions, if the fit between the face and the mask is not good, additional force may be required to achieve a seal, or the mask may leak. In addition, if the shape of the seal-forming structure does not match the shape of the patient, it may wrinkle or bend during use, causing leaks.

[0047] Another type of seal-forming structure may include friction-fit elements, for example for insertion into a nostril, however some patients find these uncomfortable.

[0048] Another form of seal-forming structure may use an adhesive to achieve a seal. Some patients may find it inconvenient to constantly apply and remove adhesive from their face.

[0049] A series of patient interface seal forming structure technologies are disclosed in the following patent applications assigned to ResMed Limited: WO 1998 / 004,310; WO 2006 / 074,513; WO 2010 / 135,785.

[0050] One form of nasal pillow is found in the Adam Circuit manufactured by Puritan Bennett. Another nasal pillow or nasal spray is the subject of U.S. Patent 4,782,832 (Trimble et al.), assigned to Puritan-Bennett Corporation.

[0051] ResMed Inc. already manufactures the following products in combination with nasal pillows: SWIFT TM Nasal pillow mask, SWIFT TMII nasal pillow mask, SWIFT TM LT nasal pillow mask, SWIFT TM FX Nasal Pillows Mask and MIRAGE LIBERTY TM Full face mask. The following patent applications assigned to ResMed Ltd. describe examples of nasal pillow masks: International Patent Application WO 2004 / 073,778 (which describes the ResMed Ltd. SWIFT TM Other aspects of nasal pillows); U.S. Patent Application 2009 / 0044808 (which describes ResMed Inc. SWIFT TM LT nasal pillows); International Patent Applications WO 2005 / 063,328 and WO 2006 / 130,903 (which describe the MIRAGE LIBERTY TM Other aspects of full-face masks); International patent application WO 2009 / 052,560 (which describes the SWIFT TM Other aspects of the FX nasal pillows).

[0052] 2.2.3.1.2 Positioning and stabilization

[0053] The seal-forming structure of the patient interface for positive air pressure therapy is subjected to the corresponding force of air pressure to break the seal. Therefore, various techniques have been used to position the seal-forming structure and maintain it in a sealing relationship with the appropriate part of the face.

[0054] One technique is to use an adhesive. See, for example, U.S. Patent Application Publication No. US2010 / 0000534. However, the use of an adhesive may be uncomfortable for some people.

[0055] Another technique is to use one or more straps and / or stabilizing harnesses.Many such harnesses suffer from one or more of poor fit, bulk, discomfort, and awkward use.

[0056] 2.2.3.2 Respiratory Pressure Therapy (RPT) Devices

[0057] Respiratory pressure therapy (RPT) devices can be used alone or as part of a system to deliver one or more of the above-mentioned therapies, such as by operating the device to generate an airflow for delivery to an airway interface. The air flow can be pressurized. Examples of RPT devices include CPAP devices and ventilators.

[0058] Air pressure generators are known in a range of applications, such as industrial-scale ventilation systems. However, air pressure generators for medical applications have specific requirements that are not met by more general air pressure generators, such as reliability, size and weight requirements for medical devices. Furthermore, even devices designed for medical use may have disadvantages with respect to one or more of the following: comfort, noise, ease of use, efficacy, size, weight, manufacturability, cost and reliability.

[0059] An example of a special requirement for certain RPT devices is noise.

[0060] Table of noise output levels of existing RPT devices (one sample only, measured at 10 cmH2O in CPAP mode using the test method specified in ISO 3744).

[0061] RPT device name A-weighted sound pressure level dB(A) Year(approx.) <![CDATA[C-Series Tango TM > 31.9 2007 <![CDATA[C-Series Tango with Humidifier TM > 33.1 2007 <![CDATA[S8 Escape TM II]]> 30.5 2005 <![CDATA[With H4i TM S8 Escape of the humidifier TM II]]> 31.1 2005 <![CDATA[S9 AutoSet TM ]]> 26.5 2010 <![CDATA[With H5i TM S9 AutoSet of humidifier TM > 28.6 2010

[0062] One known RPT device for treating sleep apnea is the S9 sleep therapy system manufactured by ResMed Limited. Another example of an RPT device is a ventilator. TM The ventilator in the range of adult and pediatric ventilators can provide support for invasive and non-invasive non-dependent ventilation to a range of patients for the treatment of a variety of conditions such as, but not limited to, NMD, OHS and COPD.

[0063] ResMed Elisée TM 150 ventilator and ResMed VS III TM The ventilator can provide support for invasive and non-invasive dependent ventilation suitable for adult or pediatric patients for the treatment of a variety of diseases. These ventilators S provide volume and pressure ventilation modes with single or dual channel circuits. The RPT device typically includes a pressure generator, such as an electric blower or a compressed gas reservoir, and is configured to supply an air flow to the patient's airway. In some cases, the air flow can be supplied to the patient's airway under positive pressure. The outlet of the RPT device is connected to a patient interface such as described above via an air circuit.

[0064] The designer of the device may be provided with an infinite number of choices that can be made. Design criteria often conflict, which means that some design choices are far from conventional or unavoidable. In addition, some aspects of comfort and efficacy may be highly sensitive to small and subtle changes in one or more parameters.

[0065] 2.2.3.3 Humidifier

[0066] Delivering an air stream without humidification may result in airway drying. Using a humidifier with an RPT device and a patient interface produces humidified gas that minimizes drying of the nasal mucosa and increases patient airway comfort. Additionally, in colder climates, warm air typically applied to the facial area in and around the patient interface is more comfortable than cold air.

[0067] A range of artificial humidification devices and systems are known, however they may not meet the specific requirements of a medical humidifier.

[0068] Medical humidifiers are used to increase the humidity and / or temperature of an air stream relative to ambient air when needed, typically where a patient may be asleep or resting (e.g., in a hospital). Medical humidifiers for bedside placement can be very small. Medical humidifiers can be configured to only humidify and / or heat the air stream delivered to the patient, without humidifying and / or heating the patient's surroundings. Room-based systems (e.g., saunas, air conditioners, or evaporative coolers), for example, can also humidify the air that the patient breathes, but these systems also humidify and / or heat the entire room, which may cause discomfort to the occupants. In addition, medical humidifiers may have more stringent safety restrictions than industrial humidifiers.

[0069] Although many medical humidifiers are known, they may have one or more disadvantages. Some medical humidifiers may provide inadequate humidification, and some may be difficult or inconvenient to use by patients.

[0070] 2.2.3.4 Data Management

[0071] There may be many clinical reasons to obtain data to determine whether a patient being treated with a prescribed respiratory therapy is "compliant," such as if the patient has used their RPT device in accordance with one or more "compliance rules." One example of a compliance rule for CPAP therapy is a requirement that the patient use the RPT device for at least four hours each night for at least 21 or 30 consecutive days in order for the patient to comply. To determine the patient's compliance, a provider of the RPT device, such as a health care provider, may manually obtain data describing the use of the RPT device for the patient's treatment, calculate usage over a predetermined time period and compare to the compliance rules. Once the health care provider has determined that the patient has used their RPT device in accordance with the compliance criteria, the health care provider may inform the patient of the third part of compliance.

[0072] There are other aspects of patient treatment that may benefit from communication of treatment data to a third party or external system.

[0073] Existing methods of communicating and managing such data can be one or more of the following: expensive, time consuming, and error prone.

[0074] 2.2.3.5 Mandibular reduction

[0075] A mandibular repositioning device (MRD) or mandibular advancement device (MAD) is one of the treatment options for sleep apnea and snoring. It is an adjustable oral appliance available from a dentist or other supplier that holds the mandible (lower jaw) in a forward position during sleep. An MRD is a removable device that the patient inserts into their mouth before falling asleep and removes after sleep. Therefore, an MRD is not designed to be worn all the time. MRDs can be custom made or produced in a standard form and include a bite impression portion designed to allow fit to the patient's teeth. This mechanical protrusion of the mandible expands the space behind the tongue, exerts tension on the pharyngeal walls to reduce collapse of the airway and reduce vibrations of the palate.

[0076] In some examples, the mandibular advancement device may include an upper splint intended to engage or cooperate with teeth on the upper jaw or maxilla and a lower splint intended to engage or cooperate with teeth on the upper jaw or mandible. The upper splint and the lower splint are laterally connected together by a pair of connecting rods. The pair of connecting rods are symmetrically fixed to the upper splint and the lower splint.

[0077] In this design, the length of the connecting rod is selected so that when the MRD is placed in the patient's mouth, the mandible remains in an anteriorly displaced position. The length of the connecting rod can be adjusted to change the degree of protrusion of the mandible. The dentist can determine the degree of protrusion of the mandible, which will determine the length of the connecting rod.

[0078] Some MRDs are constructed to push the mandible forward relative to the maxilla, while other MADs (e.g., ResMed Narval CC TM The MRD) is designed to hold the mandible in a forward position. The device also reduces or minimizes dental and temporomandibular joint (TMJ) side effects. Therefore, it is configured to minimize or prevent any movement of one or more teeth.

[0079] 2.2.3.6 Ventilation technology

[0080] Some forms of patient interface systems may include a vent to allow flushing of exhaled carbon dioxide. The vent may allow gas to flow from an interior space (eg, a plenum) of the patient interface to a space outside the patient interface, such as to the environment.

[0081] The vent may include an orifice through which gas may flow when the mask is used. Many such vents are noisy. Others may become blocked when in use, thereby providing insufficient flushing. Some vents may disrupt the sleep of the patient's 1000 bed partner 1100, for example by making noise or by gathering airflow.

[0082] ResMed Inc. has developed many improved mask ventilation technologies. See, for example, 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. US2009 / 0050156; U.S. Patent Application Publication No. 2009 / 0044808.

[0083] Noise table of existing masks (ISO 17510-2:2007, pressure of 10cmH2O at 1m)

[0084]

[0085] (*One sample only, measured at 10 cmH2O in CPAP mode using the test method specified in ISO 3744)

[0086] The following lists the sound pressure values ​​of various objects

[0087]

[0088] 2.2.4 Screening, diagnosis and monitoring systems

[0089] Polysomnography (PSG) is a conventional system for diagnosing and monitoring cardiopulmonary diseases, and usually involves professional clinical medical staff who apply the system. PSG usually involves placing 15 to 20 contact sensors on the patient to record various body signals, such as electroencephalogram (EEG), electrocardiogram (ECG), electrooculogram (EOG), electromyogram (EMG), etc. PSG for sleep apnea has involved two nights of observation of the patient in the clinic, i.e. one night of pure diagnosis and the second night when the treatment parameters are determined by the clinician. PSG is therefore expensive and inconvenient. In particular, it is not suitable for home screening / diagnosis / monitoring of sleep apnea.

[0090] Screening and diagnosis generally describe the identification of a condition from its signs and symptoms. Screening typically gives a true / false result indicating whether a patient's SDB is severe enough to warrant further investigation, while diagnosis can yield clinically actionable information. Screening and diagnosis tend to be a one-time process, while monitoring the progression of a condition can continue indefinitely. Some screening / diagnostic systems are only for screening / diagnosis, while some can also be used for monitoring.

[0091] Clinical experts can appropriately screen, diagnose or monitor patients based on visual observation of PSG signals. However, there are situations where clinical experts may not be available or clinical experts may not be affordable. Different clinical experts may disagree on a patient's condition. In addition, a given clinical expert may apply different criteria at different times. 3. Summary of the invention

[0092] The present technology is intended to provide a medical device for screening, diagnosing, monitoring, ameliorating, treating or preventing respiratory disorders with improved one or more of comfort, cost, efficacy, ease of use and manufacturability.

[0093] A first aspect of the present technology relates to a device for screening, diagnosing, monitoring, ameliorating, treating or preventing a respiratory disorder.

[0094] Another aspect of the present technology relates to methods for screening, diagnosing, monitoring, ameliorating, treating or preventing breathing disorders.

[0095] One aspect of some forms of the present technology is to provide methods and / or apparatus for improving patient compliance with respiratory therapy.

[0096] Another aspect of the present technology relates to a CPAP system for providing positive pressure air for respiratory therapy to a patient, comprising a RPT device configured to provide a flow of air at a therapeutic pressure, a patient interface forming an inflatable chamber that can be pressurized to the therapeutic pressure, the patient interface including a seal-forming structure that is constructed and arranged to form a seal with a patient's facial area surrounding an entrance to the patient's airway, an air delivery tube configured to convey the flow of air at the therapeutic pressure from the RPT device to the patient interface, a heat and moisture exchanger (HME) constructed and arranged to retain moisture from an exhaled air flow from the patient, wherein the retained moisture from the HME is returned to the air flow for humidification, a controllable heater configured and arranged to heat the HME and / or heat air entering the HME, and a controller configured to regulate heating of the controllable heater to regulate moisture returned from the HME to the air flow for humidification.

[0097] The described methods, systems, devices and apparatus may be implemented to improve the functionality of a processor, such as a processor of a dedicated computer, a respiratory monitor and / or a respiratory therapy device. In addition, the described methods, systems, devices and apparatus may provide improvements in the art of automated management, monitoring and / or treatment of respiratory conditions, including, for example, sleep-disordered breathing.

[0098] Of course, parts of various aspects can form sub-aspects of the technology of the present invention. In addition, each of the sub-aspects and / or aspects can be combined in various ways and also constitute additional aspects or sub-aspects of the technology.

[0099] Other features of the inventive technology will become apparent by considering the information contained in the following detailed description, abstract, drawings, and claims. 4. Description of the drawings

[0100] The present technology is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like reference numerals refer to similar elements, including:

[0101] 4.1 Treatment system

[0102] Figure 1A A system is shown that includes a patient 1000 wearing a patient interface 3000 in the form of nasal pillows receiving a positive pressure supply of air from a RPT device 4000. Air from the RPT device 4000 is humidified in a humidifier 5000 and delivered to the patient 1000 along an air circuit 4170. A bed partner 1100 is also shown. The patient sleeps in a supine position.

[0103] Figure 1B A system is shown that includes a patient 1000 wearing a patient interface 3000 in the manner of a nasal mask receiving a supply of air at a positive pressure from a RPT device 4000. Air from the RPT device is humidified in a humidifier 5000 and delivered to the patient 1000 along an air circuit 4170.

[0104] Figure 1C A system is shown that includes a patient 1000 wearing a patient interface 3000 in the form of a full face mask, receiving a supply of air at positive pressure from a RPT device 4000. Air from the RPT device is humidified in a humidifier 5000 and delivered to the patient 1000 along an air circuit 4170. The patient sleeps in a side-lying position.

[0105] 4.2 Respiratory system and facial anatomy

[0106] Figure 2A A schematic diagram of the human respiratory system including the nasal and oral cavities, larynx, vocal cords, esophagus, trachea, bronchi, lungs, alveolar sacs, heart, and diaphragm is shown.

[0107] Figure 2B A view of the human upper airway including the nasal cavity, nasal bones, external nasal cartilages, greater alar cartilages, nostrils, upper lip, lower lip, larynx, hard palate, soft palate, oropharynx, tongue, epiglottis, vocal cords, esophagus, and trachea is shown.

[0108] 4.3 Patient Interface

[0109] Figure 3A A patient interface in the form of a nasal mask is shown in accordance with one form of the present technology.

[0110] Figure 3B A schematic diagram of a cross section through the structure at a point is shown. The outward normal at that point is indicated. The curvature at that point has a positive sign and is Figure 3C The curvature magnitude shown is relatively large in comparison.

[0111] Figure 3C A schematic diagram of a cross section through the structure at a point is shown. The outward normal at that point is indicated. The curvature at that point has a positive sign and is Figure 3B The curvature magnitude shown is relatively small in comparison.

[0112] Figure 3D A schematic diagram of a cross section through the structure at a point is shown. The outward normal at that point is indicated. The curvature at that point has a value of zero.

[0113] Figure 3E A schematic diagram of a cross section through the structure at a point is shown. The outward normal at that point is indicated. The curvature at that point has a negative sign and is Figure 3F The curvature magnitude shown is relatively small in comparison.

[0114] Figure 3F A schematic diagram of a cross section through the structure at a point is shown. The outward normal at that point is indicated. The curvature at that point has a negative sign and is Figure 3E The curvature magnitude shown is relatively large in comparison.

[0115] Figure 3G A cushion for a mask comprising two pillows is shown. The outer surface of the cushion is indicated. The edges of the surface are indicated. The dome area and the saddle area are indicated.

[0116] Figure 3H A cushion for a face mask is shown. The outer surface of the cushion is indicated. The edge of the surface is indicated. The path on the surface between point A and point B is indicated. The straight-line distance between point A and point B is indicated. Two saddle regions and one dome region are indicated.

[0117] Fig. 3I A surface of a structure is shown, wherein the surface has a one-dimensional hole in it. The plane curves shown form the boundaries of the one-dimensional hole.

[0118] Figure 3J Shown by Fig. 3I The surface shown defines Fig. 3I A 2D hole in a structure.

[0119] Figure 3K Show Fig. 3I A perspective view of a structure including two-dimensional holes and one-dimensional holes. Also shown is a definition Fig. 3I The surface of a two-dimensional hole in a structure.

[0120] Figure 3L A mask with an inflatable bladder as a cushion is shown.

[0121] Figure 3M Shown by Figure 3L A cross section of a mask and showing the inner surface of the airbag. The inner surface defining the two-dimensional hole in the mask.

[0122] Figure 3N Shown through Figure 3L Another cross section of a mask of FIG. The inner surface is also indicated.

[0123] Fig.3O The left-hand rule is shown.

[0124] Figure 3P The right-hand rule is shown.

[0125] Figure 3Q The left ear is shown, including the left ear helix.

[0126] Figure 3R The right ear is shown, including the right ear helix.

[0127] Figure 3S A right-hand helix is ​​shown.

[0128] Figure 3T A view of a mask is shown including torsion signatures of a spatial curve defined by the edge of the sealing membrane in different regions of the mask.

[0129] Figure 3U A view of the plenum chamber 3200 is shown, showing the sagittal plane and the medial contact plane.

[0130] Figure 3V Shows Figure 3U View of the rear of the plenum chamber. The direction of view is perpendicular to the median contact plane. Figure 3V The sagittal plane divides the plenum into left-hand and right-hand sides.

[0131] Figure 3W Shown through Figure 3V The cross section of the gas-filled chamber is taken from Figure 3V The sagittal plane is shown. A "mid-contact" plane is shown. The mid-contact plane is perpendicular to the sagittal plane. The orientation of the mid-contact plane corresponds to the orientation of the chord 3210, which lies in the sagittal plane and contacts the cushion of the plenum at two points exactly in the sagittal plane: the upper point 3220 and the lower point 3230. Depending on the geometry of the cushion in the area, the mid-contact plane can be tangent at both the upper point and the lower point.

[0132] Figure 3X Shows Figure 3U The inflatable chamber 3200 is in the position of use on the face. When the inflatable chamber is in the use position, the sagittal plane of the inflatable chamber 3200 generally coincides with the central sagittal plane of the face. When the inflatable chamber is in the use position, the median contact plane generally corresponds to the "plane of the face". Figure 3XIn FIG. 3 , the inflation chamber 3200 is the inflation chamber of the nasal mask, and the upper point 3220 is approximately located on the bridge of the nose, while the lower point 3230 is located on the upper lip.

[0133] 4.4 Respiratory waveform

[0134] Figure 4 A typical breathing waveform model of a person sleeping is shown.

[0135] 4.5RPT device and humidifier

[0136] Figure 5A An exploded perspective view of an RPT device 4000 in accordance with one form of the present technology is shown.

[0137] Figure 5B A perspective view of an RPT device 4000 including an outlet muffler 4124 in accordance with one form of the present technology is shown.

[0138] Figure 5C A perspective view of an RPT device 4000 having an integrated humidifier 5000 including a water reservoir 5110 is shown in accordance with one form of the present technology.

[0139] Figure 5D is a schematic diagram of a pneumatic path for an RPT device according to one form of the present technology. Upstream and downstream directions are shown with reference to a blower and a patient interface. The blower is defined upstream of the patient interface and the patient interface is defined downstream of the blower, regardless of the actual flow direction at any particular moment. Items within the pneumatic path between the blower and the patient interface are located downstream of the blower and upstream of the patient interface.

[0140] 5E is a schematic diagram of the electrical components of an RPT device in accordance with one form of the present technology.

[0141] Fig. 5F is a schematic diagram of an algorithm implemented in an RPT device according to one form of the present technology.

[0142] Figure 5G is a schematic diagram of a humidifier according to one form of the present technology.

[0143] 4.6 CPAP system with HME and heated air delivery tube

[0144] Figure 6 is a perspective view of a CPAP system according to an example of the present technology, the CPAP system including an RPT device, a heated air delivery tube, a patient interface, and an adapter with an HME.

[0145] Figure 7 is a top view showing a heated air delivery tube and adapter according to an example of the present technology.

[0146] Figure 8 is a cross-sectional view of a heated air delivery tube and adapter according to an example of the present technology.

[0147] Fig. 9 is a cross-sectional view showing a thermistor disposed within a sheath of a heated air delivery duct according to an example of the present technology.

[0148] Fig.10 is a top view of a patient interface and adapter according to an example of the present technology.

[0149] Fig.11 is a cross-sectional view of a patient interface and adapter according to an example of the present technology.

[0150] Fig.12 is a cross-sectional view showing a pressure sensor within an RPT device according to an example of the present technology.

[0151] Fig.13 is a cross-sectional view showing a flow sensor within an RPT device according to an example of the present technology.

[0152] Fig.14 is a perspective view of a CPAP system according to an example of the present technology, the CPAP system including an RPT device, a heated air delivery tube, and a patient interface with a HME.

[0153] Fig.15 is a cross-sectional view of a patient interface with an HME according to an example of the present technology.

[0154] Fig.16 is a perspective view of a CPAP system according to an example of the present technology, the CPAP system including an RPT device, a humidifier, a heated air delivery tube, a patient interface, and an adapter with an HME.

[0155] Fig.17 is a graph showing HME temperature versus dew point for heated tube and non-heated tube arrangements according to examples of the present technology.

[0156] Figures 18 to 33 is a flow chart illustrating a control algorithm according to an example of the present technology. 5. Specific implementation methods

[0157] Before describing the present technology in more detail, it should be understood that the present technology is not limited to the specific examples described herein which may vary. It should also be understood that the terms used in the present invention are only used for the purpose of describing the specific examples discussed herein and are not intended to be limiting.

[0158] The following description is provided about various examples that can share one or more common characteristics and / or features. It should be understood that one or more features of any example can be combined with one or more features of another example or other examples. In addition, any single feature or combination of features in any example can constitute a further example.

[0159] 5.1 Treatment

[0160] In one form, the present technology includes a method for treating a breathing disorder, the method comprising the step of applying positive pressure to an airway entrance of a patient 1000 .

[0161] In certain examples of the present technology, a supply of air under positive pressure is provided to the patient's nasal passages via one or both nostrils.

[0162] In some examples of the present technology, mouth breathing is limited, restricted or prevented.

[0163] 5.2 Treatment system

[0164] In one form, the present technology includes an apparatus or device for treating a respiratory disorder. The apparatus or device may include an RPT device 4000 for supplying pressurized air to a patient 1000 via an air circuit 4170 leading to a patient interface 3000, e.g., see Figures 1A to 1C .

[0165] 5.3 Patient Interface

[0166] 3A shows that a non-invasive patient interface 3000 according to one aspect of the present technology includes the following functional aspects: a seal-forming structure 3100, an inflatable chamber 3200, a positioning and stabilizing structure 3300, a vent 3400, a connection port 3600 for connecting to a form of air circuit 4170, and a forehead support 3700. In some forms, the functional aspects may be provided by one or more physical components. In some forms, one physical component may provide one or more functional aspects. When in use, the seal-forming structure 3100 is arranged to surround the entrance of the patient's airway so as to facilitate the supply of air under positive pressure to the airway.

[0167] If a patient interface is unable to comfortably deliver a minimum level of positive pressure to the airway, the patient interface may not be suitable for respiratory pressure therapy.

[0168] A patient interface 3000 in accordance with one form of the present technology is constructed and arranged to provide a supply of air at a positive pressure of at least 6 cmH2O relative to ambient.

[0169] A patient interface 3000 in accordance with one form of the present technology is constructed and arranged to provide a supply of air at a positive pressure of at least 10 cmH2O relative to ambient.

[0170] 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.

[0171] 5.4RPT device

[0172] An exploded view of an RPT device 4000 according to one aspect of the present technology is shown in FIG. Figure 5A The RPT device 4000 may include mechanical, pneumatic, and / or electrical components and be configured to execute one or more algorithms. The RPT device 4000 may be configured to generate an air flow for delivery to the airway of a patient, for example, for treating one or more respiratory conditions described elsewhere in this document.

[0173] In one form, the RPT device 4000 is constructed and arranged to deliver an air flow 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.

[0174] The RPT device 4000 may include an outer housing having one or more panels, such as a main panel 4010, a front panel 4012, and a side panel 4014. The RPT device 4000 may also include an outlet silencer 4124, such as Figure 5A and Figure 5B The outlet silencer 4124 may be removable and replaced with a water reservoir 5110 (see Figure 5C ). In this form, the RPT device 4000 may be considered to include an integrated humidifier 5000. Thus, the RPT device 4000 may be used with or without humidification, depending on whether the water reservoir 5110 or the outlet muffler 4124, respectively, is attached. Preferably, the RPT device 4000 includes a chassis 4016 that supports one or more internal components of the RPT device 4000. In one form, the RPT device 4000 includes a pressure generator 4140, which may be housed in a pneumatic block 4020 coupled to the chassis 4016.

[0175] Additional examples and details of exemplary RPT devices are described in PCT Publication WO 2015 / 089582, the entire contents of which are incorporated herein by reference.

[0176] The pneumatic path of the RPT device 4000 (e.g., Figure 5D41) may include an inlet air filter 4112, an inlet muffler 4122, a pressure generator 4140 (preferably a blower 4142) capable of supplying air at a positive pressure, and an outlet muffler 4124 (or a water reservoir 5110 if humidification is required). One or more transducers 4270, such as pressure sensors and flow sensors, may be included in the pneumatic path. The pneumatic path may also include an anti-spillback valve 4160 to prevent water from the humidifier 5000 from overflowing back into the electrical components of the RPT device 4000.

[0177] As shown in FIG. 5E , the RPT device 4000 may have a power supply 4210, one or more input devices 4220, a central controller 4230, a treatment device controller 4240, a pressure generator 4140, one or more protection circuits 4250, a memory 4260, a converter 4270, a data communication interface 4280, and one or more output devices 4290. The electrical components 4200 may be mounted on a single printed circuit board assembly (PCBA) 4202 (e.g., see Figure 5A ). In an alternative form, the RPT device 4000 may include more than one PCBA 4202.

[0178] 5.4.1 Mechanical and pneumatic components of RPT device

[0179] The RPT device may include one or more of the following components in an integral unit. In an alternative form, one or more of the following components may be provided as separate units.

[0180] 5.4.1.1 Air filter

[0181] An RPT device according to one form of the present technology may include an air filter 4110, or multiple air filters 4110.

[0182] In one form, the inlet air filter 4112 is positioned at the beginning of the pneumatic path upstream of the pressure generator 4140 .

[0183] In one form, an outlet air filter 4114 , such as an antimicrobial filter, is positioned between the outlet of the pneumatic block 4020 and the patient interface 3000 .

[0184] 5.4.1.2 Silencer

[0185] An RPT device according to one form of the present technology may include a silencer 4120 or a plurality of silencers 4120 .

[0186] In one form of the present technology, the inlet muffler 4122 is positioned in the pneumatic path upstream of the pressure generator 4140 .

[0187] In one form of the present technology, an outlet muffler 4124 is positioned in the pneumatic path between the pressure generator 4140 and the patient interface 3000 .

[0188] 5.4.1.3 Pressure generator

[0189] In one form of the present technology, the pressure generator 4140 for generating an air flow or air supply under positive pressure is a controllable blower 4142. For example, the blower 4142 may include a brushless DC motor 4144 having one or more impellers. These impellers may be located in a volute. The blower is capable of delivering an air supply, for example, at a rate of up to about 120 liters per minute and at a positive pressure in the range of about 4 cmH2O to about 20 cmH2O or in other forms up to about 30 cmH2O. The blower may be as described in any of the following patents or patent applications, which are incorporated herein by reference in their entirety: U.S. Patent No. 7,866,944; U.S. Patent No. 8,638,014; U.S. Patent No. 8,636,479; and PCT Patent Application No. WO 2013 / 020167.

[0190] The pressure generator 4140 is under the control of the treatment device controller 4240.

[0191] In other words, the pressure generator 4140 may be a piston driven pump, a pressure regulator connected to a high pressure source (eg, a compressed air reservoir), or a bellows.

[0192] 5.4.1.4 Converter

[0193] The transducer may be internal to the RPT device, or external to the RPT device. An external transducer may be located, for example, on or form part of an air circuit such as a patient interface. An external transducer may be in the form of a non-contact sensor, such as a Doppler radar motion sensor that sends or transmits data to the RPT device.

[0194] In one form of the present technology, one or more transducers 4270 may be positioned upstream and / or downstream of the pressure generator 4140. The one or more transducers 4270 may be constructed and arranged to generate a signal representative of a characteristic of the gas flow, such as flow, pressure, or temperature, at that point in the pneumatic path.

[0195] In one form of the present technology, one or more transducers 4270 may be positioned proximal to the patient interface 3000 .

[0196] In one form, the signal from converter 4270 may be filtered, such as by low pass filtering, high pass filtering, or band pass filtering.

[0197] 5.4.1.4.1 Flow sensor

[0198] A flow sensor 4274 according to the present technology may be based on a differential pressure transducer, such as the SDP600 series differential pressure transducer from SENSIRION.

[0199] In one form, a signal representing flow rate is received from the flow sensor 4274 by the central controller 4230.

[0200] 5.4.1.4.2 Pressure sensor

[0201] A pressure sensor 4272 according to the present technology is positioned in fluid communication with the pneumatic path. An example of a suitable pressure sensor is a transducer from the ASDX series from HONEYWELL. An alternative suitable pressure sensor is a transducer from the NPA series from GENERALELECTRIC.

[0202] In one form, signals from pressure sensor 4272 may be received by central controller 4230 .

[0203] 5.4.1.4.3 Motor speed converter

[0204] In one form of the present technology, a motor speed converter 4276 is used to determine the rotational speed of the motor 4144 and / or blower 4142. A motor speed signal from the motor speed converter 4276 may be provided to the treatment device controller 4240. The motor speed converter 4276 may be, for example, a speed sensor such as a Hall effect sensor.

[0205] 5.4.1.5 Anti-overflow valve

[0206] In one form of the present technology, an anti-spillback valve 4160 is positioned between the humidifier 5000 and the pneumatic block 4020. The anti-spillback valve is constructed and arranged to reduce the risk of water flowing upstream from the humidifier 5000 to the motor 4144, for example.

[0207] 5.4.2 RPT device electrical components

[0208] 5.4.2.1 Power supply

[0209] The power source 4210 may be positioned inside or outside of the outer housing 4010 of the RPT device 4000 .

[0210] In one form of the present technology, power supply 4210 provides power only to RPT device 4000. In another form of the present technology, power supply 4210 provides power to both RPT device 4000 and humidifier 5000.

[0211] 5.4.2.2 Input device

[0212] In one form of the present technology, the RPT device 4000 includes one or more input devices 4220 in the form of buttons, switches, or dials to allow a person to interact with the device. The buttons, switches, or dials may be physical devices or software devices accessed via a touch screen. In one form, the buttons, switches, or dials may be physically connected to the external housing 4010, or in another form, may be in wireless communication with a receiver that is electrically connected to a central controller 4230.

[0213] In one form, input device 4220 may be constructed or arranged to allow a person to select values ​​and / or menu options.

[0214] 5.4.2.3 Central Controller

[0215] In one form of the present technology, the central controller 4230 is one or more processors suitable for controlling the RPT device 4000.

[0216] Suitable processors may include x86 Intel processors, -M processor, such as the STM32 series microcontroller from ST MICROELECTRONIC. In some optional forms of the present technology, a 32-bit RISC CPU such as the STR9 series microcontroller from ST Microelectronics, or a 16-bit RISC CPU such as the MSP430 series microcontroller from Texas Instruments may also be suitable.

[0217] In one form of the present technology, the central controller 4230 is a dedicated electronic circuit.

[0218] In one form, the central controller 4230 is an application specific integrated circuit. In another form, the central controller 4230 includes discrete electronic components.

[0219] The central controller 4230 may be configured to receive input signals from one or more converters 4270 , one or more input devices 4220 , and the humidifier 5000 .

[0220] The central controller 4230 may be configured to provide output signals to one or more output devices 4290 , the treatment device controller 4240 , the data communication interface 4280 , and the humidifier 5000 .

[0221] In some forms of the present technology, the central controller 4230 is configured to implement one or more methods described herein, such as one or more algorithms 4300 represented as computer programs stored in a non-transitory computer readable storage medium such as memory 4260. In some forms of the present technology, the central controller 4230 may be integrated with the RPT device 4000. However, in some forms of the present technology, some of the methods may be performed by a remotely located device. For example, the remotely located device may determine a control setting for the ventilator or detect a breathing-related event by analyzing against stored data, such as from any of the sensors described herein.

[0222] 5.4.2.4 Clock

[0223] The RPT device 4000 may include a clock 4232 connected to a central controller 4230 .

[0224] 5.4.2.5 Treatment device controller

[0225] In one form of the present technology, the treatment device controller 4240 is a treatment control module 4330 that forms part of the algorithm 4300 executed by the central controller 4230.

[0226] In one form of the present technology, the treatment device controller 4240 is a dedicated motor control integrated circuit. For example, in one form, the MC33035 brushless DC motor controller manufactured by ONSEMI is used.

[0227] 5.4.2.6 Protection circuit

[0228] One or more protection circuits 4250 in accordance with the present technology may include electrical protection circuits, temperature and / or pressure safety circuits.

[0229] 5.4.2.7 Memory

[0230] According to one form of the present technology, the RPT device 4000 includes memory 4260, such as non-volatile memory. In some forms, the memory 4260 may include battery-powered static RAM. In some forms, the memory 4260 may include volatile RAM.

[0231] Memory 4260 may be located on PCBA 4202. Memory 4260 may be in the form of EEPROM or NAND flash memory.

[0232] Additionally or alternatively, the RPT device 4000 includes memory 4260 in a removable form, such as a memory card made in accordance with the Secure Digital (SD) standard.

[0233] In one form of the present technology, the memory 4260 serves as a non-transitory computer-readable storage medium on which are stored computer program instructions representing one or more of the methods described herein, such as one or more algorithms 4300 .

[0234] 5.4.2.8 Data Communication System

[0235] In one form of the present technology, a data communication interface 4280 is provided and connected to the central controller 4230. The data communication interface 4280 may be connected to a remote external communication network 4282 and / or a local external communication network 4284. The remote external communication network 4282 may be connected to a remote external device 4286. The local external communication network 4284 may be connected to a local external device 4288.

[0236] In one form, the data communications interface 4280 is part of the central controller 4230. In another form, the data communications interface 4280 is separate from the central controller 4230 and may include an integrated circuit or processor.

[0237] In one form, remote external communication network 4282 is the Internet. Data communication interface 4280 may be connected to the Internet using wired communication (eg, via Ethernet or fiber optic) or wireless protocols (eg, CDMA, GSM, LTE).

[0238] In one form, the local external communications network 4284 utilizes one or more communications standards, such as Bluetooth or consumer infrared protocols.

[0239] In one form, the remote external device 4286 can be one or more computers, such as a cluster of network computers. In one form, the remote external device 4286 can be a virtual computer rather than a physical computer. In either case, this remote external device 4286 can be accessed by appropriately authorized personnel (such as a clinician).

[0240] The local external device 4288 may be a personal computer, a mobile phone, a tablet or a remote control device.

[0241] 5.4.2.9 Output devices including optional displays and alarms

[0242] Output devices 4290 according to the present technology may take the form of one or more of visual, audio, and tactile units.The visual display may be a liquid crystal display (LCD) or a light emitting diode (LED) display.

[0243] 5.4.2.9.1 Display Driver

[0244] The display driver 4292 receives as input characters, symbols, or images for display on the display 4294 and converts them into commands that cause the display 4294 to display those characters, symbols, or images.

[0245] 5.4.2.9.2 Display

[0246] The display 4294 is configured to visually display characters, symbols, or images in response to commands received from the display driver 4292. For example, the display 4294 may be an eight-segment display, in which case the display driver 4292 converts each character or symbol (such as the number "0") into eight logic signals indicating whether the eight corresponding segments are to be activated to display the particular character or symbol.

[0247] 5.4.3RPT device algorithm

[0248] As described above, in some forms of the present technology, the central controller 4230 may be configured to implement one or more algorithms 4300 expressed as computer programs stored in a non-transitory computer-readable storage medium (e.g., memory 4260). The algorithms 4300 are generally grouped into groups called modules, see, for example, Fig. 5F .

[0249] 5.4.3.1 Preprocessing Module

[0250] A pre-processing module 4310 according to one form of the present technology receives as input a signal from a transducer 4270 (e.g., a flow sensor 4274 or a pressure sensor 4272) and performs one or more processing steps to calculate one or more output values ​​to be used as input to another module (e.g., a treatment engine module 4320).

[0251] In one form of the present technology, the output values ​​include interface or mask pressure Pm, respiratory flow Qr and leak flow Ql.

[0252] In various forms of the present technology, the pre-processing module 4310 includes one or more of the following algorithms: pressure compensation 4312 , vent flow estimation 4314 , leak flow estimation 4316 , and respiratory flow estimation 4318 .

[0253] 5.4.3.1.1 Pressure compensation

[0254] In one form of the present technology, the pressure compensation algorithm 4312 receives as input a signal indicative of the pressure in the pneumatic path proximal to the pneumatic block outlet. The pressure compensation algorithm 4312 estimates the pressure drop through the air circuit 4170 and provides as output an estimated pressure Pm in the patient interface 3000.

[0255] 5.4.3.1.2 Ventilation Flow Estimation

[0256] In one form of the present technology, the vent flow estimation algorithm 4314 receives as input an estimated pressure Pm in the patient interface 3000 and estimates a ventilation flow Qv of air from the vent 3400 in the patient interface 3000 .

[0257] 5.4.3.1.3 Leakage flow estimation

[0258] In one form of the present technology, the leakage flow estimation algorithm 4316 receives the total flow Qt and the exhaust flow Qv as inputs and provides an estimate of the leakage flow Ql as output. In one form, the leakage flow estimation algorithm estimates the leakage flow Ql by averaging the difference between the total flow Qt and the ventilation flow Qv over a period of time long enough to include several respiratory cycles (e.g., about 10 seconds).

[0259] In one form, the leak flow estimation algorithm 4316 receives as input the total flow Qt, the ventilation flow Qv, and the estimated pressure Pm in the patient interface 3000, and provides as output a leak flow Ql by calculating a 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 quotient of the low-pass filtered non-ventilation 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, where the low-pass filter time constant has a value long enough to include several respiratory cycles (e.g., about 10 seconds). The leak flow Ql can be estimated as the product of the leak conductance and the pressure Pm function.

[0260] 5.4.3.1.4 Respiratory flow estimation

[0261] In one form of the present technology, the respiratory flow estimation algorithm 4318 receives as input the total flow Qt, the ventilation flow Qv, and the leak flow Ql, and estimates the air respiratory flow Qr to the patient by subtracting the ventilation flow Qv and the leak flow Ql from the total flow Qt.

[0262] 5.4.3.2 Treatment Engine Module

[0263] In one form of the present technology, therapy engine module 4320 receives as input one or more of pressure Pm in patient interface 3000 and air respiratory flow Qr to the patient, and provides as output one or more therapy parameters.

[0264] In one form of the present technology, the treatment parameter is treatment pressure Pt.

[0265] In one form of the present technology, the therapy parameter is one or more of pressure amplitude, basal pressure, and target ventilation.

[0266] In various forms, the therapy engine module 4320 includes one or more of the following algorithms: phase determination 4321, waveform determination 4322, ventilation determination 4323, inspiratory flow limitation determination 4324, apnea / hypopnea determination 4325, snoring determination 4326, airway patency determination 4327, target ventilation determination 4328 and therapy parameter determination 4329.

[0267] 5.4.3.2.1 Phase determination

[0268] In one form of the present technology, the RPT device 4000 is phase indeterminate.

[0269] In one form of the present technology, the phase determination algorithm 4321 receives as input a signal indicative of respiratory flow Qr and provides as output the phase Φ of the current respiratory cycle of the patient 1000.

[0270] In some forms, referred to as discrete phase determination, the phase output Φ is a discrete variable. One implementation of discrete phase determination provides a two-value phase output Φ having an inspiratory or expiratory value, for example, values ​​represented as 0 and 0.5 revolutions, respectively, upon detection of the onset of spontaneous inspiration and expiration, respectively. The RPT device 4000 that performs "triggering" and "cycling" effectively performs discrete phase determination because the trigger and cycle points are the moments of phase change from exhalation to inspiration and from inspiration to exhalation, respectively. In one implementation of two-value phase determination, when the respiratory flow Qr has a value exceeding a positive threshold, the phase output Φ is determined to have a discrete value of 0 (thereby "triggering" the RPT device 4000), and when the respiratory flow Qr has a value more negative than a negative threshold, the phase output Φ is determined to have a discrete value of 0.5 (thereby "cycling" the RPT device 4000). The inspiratory time Ti and the expiratory time Te can be estimated as typical values ​​over many respiratory cycles of the time spent for the phase Φ to be equal to 0 (indicating inspiration) and 0.5 (indicating exhalation), respectively.

[0271] Another implementation of discrete phase determination provides a three-valued phase output Φ having one of values ​​of inspiration, midpoint of inspiration pause, and expiration.

[0272] In other forms referred to as continuous phase determination, the phase output Φ is a continuous value, for example varying from 0 to 1 turn or 0 to 2π radians. The RPT device 4000 performing continuous phase determination can trigger and cycle when the continuous phase reaches 0 and 0.5 turns, respectively. In one implementation of continuous phase determination, a fuzzy logic analysis of the respiratory flow Qr is used to determine the continuous values ​​of the phase Φ. The continuous values ​​of the phase determined in this implementation are generally referred to as "fuzzy phase". In one implementation of the fuzzy phase determination algorithm 4321, the following rules are applied to the respiratory flow Qr:

[0273] 1. If the respiratory flow is zero and increases rapidly, the phase is 0 turns.

[0274] 2. If the respiratory flow is largely positive and stable, the phase is 0.25 turns.

[0275] 3. If the respiratory flow is zero and decreases rapidly, the phase is 0.5 turns.

[0276] 4. If the respiratory flow is largely negative and stable, the phase is 0.75 turns.

[0277] 5. If the respiratory flow is zero and stable and the 5-second low-pass filtered absolute value of the respiratory flow is large, the phase is 0.9 turns.

[0278] 6. If the respiratory flow is positive and it is the exhalation phase, the phase is 0 revolutions.

[0279] 7. If the respiratory flow is negative and it is the inspiratory phase, the phase is 0.5 turns.

[0280] 8. If the absolute value of a 5 second low pass filter of the respiratory flow is large and the phase increases at a steady rate equal to the patient's respiratory rate, then the low pass filter has a time constant of 20 seconds.

[0281] The output of each rule can be represented as a vector whose phase is the result of the rule and whose magnitude is the ambiguity of the rule being true. The ambiguity of respiratory flow "large", "stable", etc. is determined using appropriate membership functions. The results of the rules, represented as vectors, are then combined by some function, such as taking the centroid. In such a combination, the rules can be weighted equally, or differently.

[0282] In another implementation of continuous phase determination, as described above, the phase Φ is first estimated discretely from the respiratory flow Qr, as is the inspiratory time Ti and the expiratory time Te. The continuous phase Φ at any time is determined as half of the proportion of the inspiratory time Ti that has passed since the previous triggering time, or 0.5 turns plus half of the proportion of the expiratory time Te that has passed since the previous cycle time (whichever is newer).

[0283] 5.4.3.2.2 Waveform determination

[0284] In one form of the present technology, the therapy parameter determination algorithm 4329 provides an approximately constant therapy pressure throughout the patient's breathing cycle.

[0285] In other forms of the present technology, the therapy control module 4330 controls the pressure generator 4140 to provide a therapy pressure Pt that varies according to the phase Φ of the patient's respiratory cycle based on the waveform template Π(Φ).

[0286] In one form of the present technology, the waveform determination algorithm 4322 provides a waveform template Π(Φ) with a value in the range of [0,1] over the domain of the phase value Φ provided by the phase determination algorithm 4321 for use by the treatment parameter determination algorithm 4329.

[0287] In one form applicable to discrete or continuous valued phases, the waveform template Π(Φ) is a square wave template having a value of 1 for phase values ​​up to and including 0.5 turns, and having a value of 0 for phase values ​​above 0.5 turns. In one form applicable to continuous valued phases, the waveform template Π(Φ) includes two smoothly curved portions, namely a smoothly curved (e.g., raised cosine) rise from 0 to 1 for phase values ​​up to 0.5 turns, and a smoothly curved (e.g., exponential) decay from 1 to 0 for phase values ​​above 0.5 turns. In one form applicable to continuous valued phases, the waveform template Π(Φ) is based on a square wave, but has a smooth rise from 0 to 1 for phase values ​​up to a "rise time" of less than 0.5 turns, and smoothly decays from 1 to 0 for phase values ​​within a "fall time" after 0.5 turns, the "fall time" being less than 0.5 turns.

[0288] In some forms of the present technology, the waveform determination algorithm 4322 selects a waveform template Π(Φ) from a library of waveform templates based on the settings of the RPT device. Each waveform template Π(Φ) in the library can be provided as a lookup table of values ​​Π relative to phase values ​​Φ. In other forms, the waveform determination algorithm 4322 calculates a "real-time" waveform template Π(Φ) using a predetermined functional form that may be parameterized by one or more parameters (e.g., a time constant of an exponential curve portion). The parameters of the functional form may be predetermined or depend on the current state of the patient 1000.

[0289] In some forms of the present technology applicable to discrete two-valued phases for inspiration (Φ=0 turns) or exhalation (Φ=0.5 turns), the waveform determination algorithm 4322 calculates a "real-time" waveform template Π as a function of both the discrete phase Φ and the time t measured since the most recent trigger moment. In one such form, the waveform determination algorithm 4322 calculates the waveform template Π(Φ, t) in both parts (inspiration and exhalation) as follows:

[0290]

[0291] where Π i (t) and Π e (t) is the inspiratory and expiratory portion of the waveform template Π(Φ, t). In one such form, the inspiratory portion of the waveform template Π i (t) is a smooth rise from 0 to 1 parameterized by the rise time, and the exhalation part of the waveform template Π e (t) is a smooth decline from 1 to 0 parameterized by the decline time.

[0292] 5.4.3.2.3 Ventilation volume determination

[0293] In one form of the present technology, the ventilation volume determination algorithm 4323 receives the respiratory flow rate Qr as an input and determines a measured value indicative of the current patient ventilation volume Vent.

[0294] In some implementations, the ventilation volume determination algorithm 4323 determines a measured value of the ventilation volume Vent, which is an estimate of the actual patient ventilation volume. One such implementation is to optionally filter half of the absolute value of the respiratory flow rate Qr by a low-pass filter (such as a second-order Bessel low-pass filter with an angular frequency of 0.11 Hz).

[0295] In other implementations, the ventilation volume determination algorithm 4323 determines a measured value of the ventilation volume Vent, which is approximately proportional to the actual patient ventilation volume. One such implementation estimates the peak respiratory flow rate Qpeak during the inspiratory portion of the cycle. This and many other procedures involving sampling the respiratory flow rate Qr produce measured values that are approximately proportional to the ventilation volume, provided that the flow waveform shape does not vary greatly (here, when the flow waveforms of normal breaths in terms of time and amplitude are similar, the shapes of two breaths are considered similar). Some simple examples include the median of the respiratory flow rate being positive, the median of the absolute value of the respiratory flow rate, and the standard deviation of the flow rate. Any linear combination of any order statistics of the absolute value of the respiratory flow rate using positive coefficients, and even some that use both positive and negative coefficients, is approximately proportional to the ventilation volume. Another example is the average of the respiratory flow rate for the middle K proportion (by time) of the inspiratory portion, where 0 < K < 1. If the flow shape remains constant, there can be any number of measured values that are exactly proportional to the ventilation volume.

[0296] 5.4.3.2.4 Inspiratory flow limit determination

[0297] In one form of the present technology, the central controller 4230 executes an inspiratory flow limit determination algorithm 4324 for determining the degree of inspiratory flow limit.

[0298] In one form, the inspiratory flow limit determination algorithm 4324 receives the respiratory flow signal Qr as an input and provides, as an output, a measure of the degree to which the inspiratory portion of the breath exhibits an inspiratory flow limit.

[0299] In one form of the present technology, the inspiratory portion of each breath is identified by a zero crossing detector. A number of evenly spaced points (e.g., sixty-five) representing time points are interpolated along the inspiratory flow-time curve of each breath by an interpolator. The curve described by the points is then scaled by a scalar to have unit length (duration / cycle) and unit area to remove the effects of changing respiratory frequency and depth. The scaled breath is then compared in a comparator with a pre-stored template representing normal unobstructed breathing. As determined by the test element, breaths from the template that deviate by more than a specified threshold (usually 1 scaling unit) at any time during inspiration due to coughing, sighing, swallowing, and hiccups are rejected. For data that is not rejected, a moving average of the first such scaling point is calculated by the central controller 4230 for several preceding inspiratory events. This is repeated for the second such point on the same inspiratory event, and so on. Thus, for example, sixty-five scaling data points are generated by the central controller 4230, and these data points represent the moving average of several preceding inspiratory events, such as three events. The moving average of the continuously updated values ​​of the (eg, sixty-five) points is hereinafter referred to as the "scaled flow", named Qs(t). Alternatively, a single inspiratory event may be used instead of a moving average.

[0300] From the scaled flow, two shape factors relevant to determining partial blockage can be calculated.

[0301] Shape Factor 1 is the ratio of the average of the middle (e.g., thirty-two) scaled flow points to the average overall (e.g., sixty-five) scaled flow points. If this ratio exceeds 1, the breath will be considered normal. If the ratio is 1 or less, the breath will be considered obstructed. A ratio of about 1.17 is considered the threshold between partially obstructed and unobstructed breaths and is equivalent to a degree of obstruction that will allow adequate oxygenation to be maintained in a typical patient.

[0302] Shape Factor 2 is calculated as the RMS deviation from unit scaled flow taken at an intermediate (e.g., thirty-two) point. An RMS deviation of about 0.2 units is considered normal. A zero RMS deviation is considered a completely flow-restricted breath. The closer the RMS deviation is to zero, the more flow-restricted the breath will be considered.

[0303] Form factors 1 and 2 may be used as alternatives or in combination. In other forms of the present technology, the number of sampling points, the number of breaths, and the number of intermediate points may be different from those described above. Furthermore, the thresholds may be different from those described.

[0304] 5.4.3.2.5 Determination of apnea and hypopnea

[0305] In one form of the present technology, the central controller 4230 executes an apnea / hypopnea determination algorithm 4325 to determine the presence of apnea and / or hypopnea.

[0306] In one form, the apnea / hypopnea determination algorithm 4325 receives as input the respiratory flow signal Qr and provides as output a flag indicating that an apnea or hypopnea has been detected.

[0307] In one form, when the function of respiratory flow Qr falls below a flow threshold for a predetermined period of time, apnea may be considered detected. The function may determine a peak flow, a relatively short-term average flow, or an intermediate flow of a relatively short-term average flow and a peak flow (e.g., RMS flow). The flow threshold may be a measure of a relatively long-term flow.

[0308] In one form, when the function of respiratory flow Qr falls below a second flow threshold within a predetermined time period, hypopnea may be considered detected. The function may determine a peak flow, a relatively short-term average flow, or an intermediate flow of a relatively short-term average flow and a peak flow (e.g., RMS flow). The second flow threshold may be a measure of a relatively long-term flow. The second flow threshold is greater than a flow threshold for detecting apnea.

[0309] 5.4.3.2.6 Determination of snoring

[0310] In one form of the present technology, the central controller 4230 executes one or more snoring determination algorithms 4326 for determining the level of snoring.

[0311] In one form, the snoring determination algorithm 4326 receives as input a signal of respiratory flow Qr and provides as output a measure of the degree to which snoring is present.

[0312] The snore determination algorithm 4326 may include a step of determining the flow signal strength in the range of 30-300 Hz. In addition, the snore determination algorithm 4326 may include a step of filtering the signal of the respiratory flow Qr to reduce background noise (eg, the sound of air flow from a blower in the system).

[0313] 5.4.3.2.7 Determination of airway patency

[0314] In one form of the present technology, the central controller 4230 executes one or more airway patency determination algorithms 4327 for determining airway patency.

[0315] In one form, the airway patency determination algorithm 4327 receives as input the respiratory flow signal Qr and determines the power of the signal within a frequency range of about 0.75 Hz and about 3 Hz. The presence of a peak in this frequency range is considered to indicate an open airway. The absence of a peak is considered to be an indication of a closed airway.

[0316] In one form, the frequency range in which the peak is sought is the frequency of a small forced oscillation in the process pressure Pt. In one implementation, the forced oscillation frequency is 2 Hz and the amplitude is about 1 cmH2O.

[0317] In one form, the airway patency determination algorithm 4327 receives as input the respiratory flow signal Qr and determines the presence or absence of a cardiogenic signal. The absence of a cardiogenic signal is considered indicative of airway closure.

[0318] 5.4.3.2.8 Determination of target ventilation

[0319] In one form of the present technology, the central controller 4230 takes as input a measured value of the current ventilation Vent and executes one or more target ventilation determination algorithms 4328 to determine a target value Vtgt for the measured ventilation.

[0320] In some forms of the present technology, there is no target ventilation determination algorithm 4328 and the target value Vtgt is predetermined, for example by hard coding during configuration of the RPT device 4000 or by manual entry via the input device 4220.

[0321] In other forms of the present technology, such as adaptive servo-ventilation (ASV), the target ventilation determination algorithm 4328 calculates the target value Vtgt from a value Vtyp indicative of the patient's typical recent ventilation.

[0322] In some forms of adaptive servo-ventilation, the target ventilation Vtgt is calculated as a high proportion of the typical recent ventilation Vtyp but less than Vtyp. The high proportion in such forms may be in the range of (80%, 100%), or (85%, 95%), or (87%, 92%).

[0323] In other forms of adaptive servo-ventilation, the target ventilation Vtgt is calculated to be slightly greater than a multiple of the typical recent ventilation Vtyp.

[0324] The typical recent ventilation Vtyp is the value around which the distribution of the current ventilation Vent measurements at multiple moments within some predetermined time scale tends to cluster, that is, a measure of the central tendency of the current ventilation measurements in the recent history. In one implementation of the target ventilation determination algorithm 4328, the recent history is on the order of a few minutes, but in any case should be longer than the time scale of the tidal increase and decrease cycle. The target ventilation determination algorithm 4328 can use a variety of known central tendency measures to determine the typical recent ventilation Vtyp from the current ventilation Vent measurements. One such measurement is the output of a low pass filter on the current ventilation Vent measurements, with a time constant equal to 100 seconds.

[0325] 5.4.3.2.9 Treatment parameter determination

[0326] In some forms of the present technology, the central controller 4230 executes one or more treatment parameter determination algorithms 4329 to determine one or more treatment parameters using values ​​returned by one or more other algorithms in the treatment engine module 4320.

[0327] In one form of the present technology, the treatment parameter is the instantaneous treatment pressure Pt. In one implementation of this form, the treatment parameter determination algorithm 4329 determines the treatment pressure Pt using the following equation

[0328] Pt=AΠ(Φ,t)+P0 (1)

[0329] in:

[0330] A is the amplitude,

[0331] Π(Φ, t) is the waveform template value (in the range of 0 to 1) at the current value of phase Φ and time t, and

[0332] P0 is the base pressure.

[0333] If the waveform determination algorithm 4322 provides the waveform template Π(Φ, τ) as a numerical lookup table indexed by phase, the treatment parameter determination algorithm 4329 applies equation (1) by locating the nearest lookup table entry to the phase current value Φ returned by the phase determination algorithm 4321, or by interpolating across two entries of the phase current value Φ.

[0334] Depending on the selected respiratory pressure therapy mode, the values ​​of amplitude A and basal pressure P0 may be set by therapy parameter determination algorithm 4329 in the following manner.

[0335] 5.4.3.3 Treatment Control Module

[0336] The therapy control module 4330 according to one aspect of the present technology receives therapy parameters as input from the therapy parameter determination algorithm 4329 of the therapy engine module 4320 and controls the pressure generator 4140 to deliver air flow in accordance with the therapy parameters.

[0337] In one form of the present technology, the therapy parameter is a therapy pressure Pt, and the therapy control module 4330 controls the pressure generator 4140 to deliver an air flow with a mask pressure Pm at the patient interface 3000 equal to the therapy pressure Pt.

[0338] 5.4.3.4 Fault Condition Detection

[0339] In one form of the present technology, the central controller 4230 executes one or more methods 4340 for detecting a fault condition. The fault condition detected by the one or more methods 4340 may include at least one of the following:

[0340] Power failure (no power or insufficient power)

[0341] Converter fault detection

[0342] Unable to detect the presence of components

[0343] Operating parameters outside the recommended range (e.g. pressure, flow, temperature, PaO2).

[0344] The test alarm fails to produce a detectable alarm signal.

[0345] Upon detecting a fault condition, the corresponding algorithm 4340 signals the presence of a fault by one or more of the following:

[0346] Activate audible, visual and / or dynamic (e.g., vibration) alarms

[0347] Send messages to external devices

[0348] Event logging

[0349] 5.5 Air circuit

[0350] The air circuit 4170 according to one aspect of the present technology is a conduit or tube that is constructed and arranged to allow air flow to flow between two components, such as the RPT device 4000 and the patient interface 3000, when in use.

[0351] 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 branches for the inspiratory and expiratory circuits. In other cases, a single branch is used.

[0352] In some forms, the air circuit 4170 may include one or more heating elements configured to heat the air in the air circuit, for example to maintain or increase the temperature of the air. The heating element may be in the form of a heating wire loop and may include one or more transducers, such as a temperature sensor. In one form, the heating wire loop may be helically wound around the axis of the air circuit 4170. The heating element may be in communication with a controller such as a central controller 4230. An embodiment of a control circuit 4170 including a heating wire loop is described in U.S. Patent 8,733,349, which is incorporated herein by reference in its entirety.

[0353] 5.5.1 Oxygen delivery

[0354] In one form of the present technology, supplemental oxygen 4180 is delivered to one or more points in the pneumatic pathway, such as upstream of the pneumatic block 4020 , the air circuit 4170 , and / or the patient interface 3000 .

[0355] 5.6 Humidification using HME and heated air delivery tube

[0356] 5.6.1 Overview of HME

[0357] Delivering an air flow without humidification may result in airway drying. A heat and moisture exchanger (HME) may be used in PAP therapy to partially recover heat and moisture present in exhaled gases from the patient's airway. When the breathable gas flow passes through the HME prior to inspiration, the heat and moisture can be retained and recirculated to the patient in a passive manner. Thus, the use of an HME can provide the required humidity and moisture (generally considered to be >10 mg / l) to most patients during PAP therapy to minimize any deleterious effects associated with PAP therapy with non-humidified ambient air.

[0358] HMEs are typically composed of foam, paper, or a material that can act as a condensation and absorption surface. The material may carry a hygroscopic salt to improve water retention. Suitable salts include calcium chloride.

[0359] A common problem with using HMEs in PAP therapy involves condensation on the patient interface in cold environments. When a patient sleeps in a cold room during PAP therapy, the room air cools the outer surfaces of the patient interface and the air delivery tubing, and each breath of cold air from the patient cools the inner surfaces of the patient interface. The colder the patient interface, the more the patient's warm, moist breath condenses on the inner surfaces of the patient interface with each exhalation. This effect is exacerbated by adding HMEs to the air delivery circuit, as moisture retention in the patient interface by the HME leads to more condensation.

[0360] In addition, the HME may include different moisture retention capabilities, from which it is necessary to select the appropriate HME capability to suit the ambient humidity. For example, one HME model may be configured for a mild environment, and another HME model may be configured for a dry environment. When the ambient humidity increases, the moisture drawn through the HME also increases, which can exacerbate condensation in the patient interface.

[0361]

[0006] Therefore, there is a need to provide for use of HMEs in PAP therapy to achieve desired patient humidification while reducing the effects of cold environments on the HME system.

[0362] 5.6.2 HME and heated air ducts

[0363] One aspect of the present technology relates to humidification using an HME and a heated air delivery tube. As described below, the heated air delivery tube heats the incoming air, which heats the inner surface of the patient interface to reduce the effect of cooling the inner surface of the patient interface on each patient inhalation. In addition, when the air entering the HME is heated, the moisture returned from the HME is reduced. As a result, the elevated air temperature provided by the heated air delivery tube can be controlled to reduce condensation on the inner surface of the patient interface and balance the moisture level inhaled by the patient.

[0364] Figure 6 and 13 A CPAP system 7000 according to an example of the present technology is shown. As shown, the CPAP system 7000 includes an RPT device 4000, a patient interface 3000, an adapter 6000 including an HME 6500, and a heated air delivery tube 4170. The heated air delivery tube 4170 and the adapter 6000 cooperate to deliver air flow from the RPT device 4000 to the patient interface 3000.

[0365] As described above, the RPT device 4000 includes a pneumatic block 4020 supported within an external housing. The blower 4142 of the pneumatic block 4020 is constructed and arranged to generate a positive pressure air flow or air supply within the range of 2-50cmH2O. In an example, the blower may include a single-stage design or a multi-stage design, for example, a two-stage or more stage design. The blower is operable to draw the air supply into the external housing, for example, through one or more air inlets in the external housing, and into its inlet (blower inlet), and provide a pressurized air supply at the outlet (blower outlet). Examples and details of exemplary RPT devices are described in PCT Publication WO 2015 / 089582, the entire contents of which are incorporated herein by reference. The blower outlet is connected to the heated air delivery tube 4170.

[0366] The air delivery tube 4170 includes a tube portion 4172, an RPT device connector / sleeve (outlet connector) 4174 adapted to connect the air delivery tube 4170 to an outlet of the RPT device 4000, and a patient interface connector / sleeve (inlet connector) 4176 adapted to connect the air delivery tube 4170 to an inlet of the patient interface 3000, for example, via a Figures 6 to 8 Adapter 6000 is shown.

[0367] In an example, the RPT device connector 4174 is constructed and arranged to form pneumatic, mechanical, and electrical connections with the RPT device 4000. These connections allow pressurized gas to flow from the RPT device 4000 to the patient interface 3000, position and secure the air delivery tube 4170 to the RPT device 4000, and provide power and signaling to the heating element and converter of the air delivery tube 4170. These connections can be made simultaneously or in series, for example, one of the mechanical, pneumatic, or electrical connections can be completed before the other connections.

[0368] Examples and details of exemplary heated air delivery ducts are described in PCT Publication No. WO 2015 / 089582, the entire contents of which are incorporated herein by reference.

[0369] In an example, the air delivery tube 4170 may include multiple wires helically wound around the axis of the delivery tube 4170, which are configured to heat the air in the air delivery tube 4170 and / or transmit signals from one or more sensors (e.g., temperature sensors, flow sensors), for example.

[0370] For example, Fig. 9 As shown in , a gas temperature sensor (e.g., a thermistor 4178) can be provided in the patient interface connector 4176 to measure the temperature of the air flow. The temperature sensed by the thermistor 4178 can be provided as a signal to the controller through the wire of the air delivery tube 4170.

[0371] Examples and details of exemplary sensors and heated air delivery ducts are described in US Pat. No. 9,903,371, the entire contents of which are incorporated herein by reference.

[0372] Patient interface 3000 includes a seal-forming structure 3100 (e.g., nasal pillows), a plenum chamber 3200, and a connection port 3600. Adapter 6000 including HME 6500 may be connected to connection port 3600, for example, via a short tube assembly and / or an elbow assembly. A vent for gas flushing may be provided to plenum chamber 3200 or adapter 6000.

[0373] In the example shown, Figure 6-8As shown in Figures 10-11, the adapter 6000 includes multiple components configured and arranged to support the HME 6500 and provide a diffused vent arrangement for gas flushing. For example, the adapter 6000 includes a vent and HME assembly 6050, a short tube assembly 6010 that provides a connection between the vent and HME assembly 6050 and the patient interface 3000, and a short tube assembly 6020 that provides a connection between the vent and HME assembly 6050 and the heated air delivery tube 4170.

[0374] In the illustrated example, the vent and HME assembly 6050 includes a connector 6060 to connect the vent and HME assembly 6050 with a stub assembly 6010, a housing 6070, a core structure 6080 that provides an orifice for vent flow, and a diffuser cap 6090 that supports a diffuser 6095 for diffusing the vent flow from the core structure 6080. The HME 6500 may be held within the vent and HME assembly 6050 by, for example, the housing 6070 and the connector 6060.

[0375] The short tube assembly 6010 includes a tube 6012 , a connector 6014 for providing a connection between the tube 6012 and the connector portion 3600 of the patient interface 3000 , and a connector 6016 for providing a connection between the tube 6012 and the vent and HME assembly 6050 , for example, via a connector 6060 .

[0376] The short tube assembly 6020 includes a tube 6022, a connector 6024 for providing a connection between the tube 6022 and the vent and HME assembly 6050 (e.g., via the core structure 6080), and a connector 6026 for providing a connection between the tube 6022 and the heated air delivery tube 4170 (e.g., via the patient interface connector 4176).

[0377] Examples and details of exemplary patient interfaces and adapters including HMEs are described in PCT Publication WO 2018 / 126295, which is incorporated herein by reference in its entirety.

[0378] In the optional example, Fig.14 and 15 As shown, HME 6500 can be positioned within the plenum 3200 of patient interface 3000. As shown, patient interface 3000 includes a seal-forming structure 3100 (e.g., a nasal plug), a nasal cushion, a plenum 3200, and a connection port 3600. Vent 3400 is used for gas flushing. In this example, HME 6500 is positioned in the flow path of the breathable gas within the plenum 3200 of patient interface 3000 and is adjacent to the entrance of the patient's airway.

[0379] like Fig.14As shown, the short tube assembly 6025 can provide a connection between the patient interface 3000 and the heated air delivery tube 4170. For example, the short tube assembly 6025 can include a connector 6027 to provide a connection to the heated air delivery tube 4170, such as via a patient interface connector 4176.

[0380] Examples and details of an exemplary patient interface including an HME within a plenum chamber are described in PCT Publication WO 2015 / 013761, which is incorporated herein by reference in its entirety.

[0381] It should be understood that the patient interface and HME may include other suitable configurations and arrangements. For example, it should be understood that the various aspects of the present technology may be suitable for use with other suitable interface arrangements and types, such as, full face / oral and nasal interfaces, nasal interfaces, nasal prongs. In addition, it should be understood that the various aspects of the present technology may be suitable for use with other suitable HME arrangements and types, such as, HMEs positioned upstream of the plenum of the patient interface (e.g., in an elbow assembly, a short tube assembly, etc.), HMEs positioned directly in the plenum of the patient interface.

[0382] The RPT device 4000, the heated air delivery tube 4170, and / or the patient interface 3000 can each include one or more transducers (e.g., temperature sensors, humidity sensors, flow sensors, respiratory rate sensors). These sensors can generate one or more output signals that can be transmitted to a controller to control the condensation level within the patient interface and the temperature and humidity of the air inhaled by the patient. For example, the controller can receive measurements of temperature and humidity in the HME system as input. The controller can be configured to execute or implement an algorithm and / or deliver one or more output signals, for example, to control the temperature of the heated air delivery tube.

[0383] In the example, Fig.12 and 13 As shown, the pneumatic block 4020 of the RPT device 4000 may include a pressure sensor 4090 and a flow sensor 4095. Fig.12 As shown, the pressure sensor 4090 can be connected to the pressure port 4092 adjacent to the outlet 4093 of the pneumatic block 4020, for example, to directly measure the static pressure perpendicular to the direction of air flow. Fig.13As shown, the flow sensor 4095 can be in communication with the flow sensor ports 4096, 4097, for example, to measure the pressure drop between the first chamber and the second chamber in the pneumatic block 4020. Other examples and details of the sensor are described in PCT Publication WO 2015 / 089582, the entire contents of which are incorporated herein by reference. The RPT device may also include a temperature sensor and / or a humidity sensor. The heated air delivery tube 4170 may include a temperature sensor, for example, a thermistor 4178, which is provided in the patient interface connector 4176 of the heated air delivery tube 4170 as described above. In an alternative example, the temperature sensor and / or humidity sensor may be provided to the downstream side of the HME 6500, i.e., the side of the HME 6500 closer to the patient. The controller may be configured to control the power to the heated air delivery tube 4170 based on feedback from one or more of these sensors, for example, ambient temperature, ambient humidity, patient settings and / or tube temperature, so as to, for example, regulate condensation and temperature / humidity of the inhaled air. It should be appreciated that one or more alternative sensors may be provided to the RPT device 4000, heated air delivery tube 4170, and / or patient interface 3000 to facilitate control.

[0384] In an environment where the temperature in the patient interface 3000 (e.g., the temperature measured on the patient side of the HME) drops below the dew point, condensation will form in the patient interface 3000 (e.g., on the interior surfaces of the plenum 3200 and / or along the interior surfaces of the elbow / stub connecting the HME to the plenum 3200 (e.g., along the stub assembly 6010). According to one aspect of the present technology, condensation is reduced or entirely eliminated by heating the incoming air with the heated air delivery tube 4170. That is, the hot incoming air will heat the interior surfaces of the patient interface 3000 such that the temperature of such interior surfaces will remain above the dew point.

[0385] Fig.17 is a graph showing an example of HME temperature versus dew point for heated tubing (e.g., heated tubing at "30°C") and non-heated tubing (e.g., heated tubing at "off") when the ambient temperature is tested below 10°C. As shown, when the HME is used with a heated air delivery tube, the temperature in the patient interface (e.g., the HME temperature measured on the patient side of the HME) remains above or close to the dew point. When the heated air delivery tube is not used with the HME, the temperature in the patient interface drops below the dew point, and condensation will occur in the patient interface.

[0386] In addition, when the air entering the HME is heated, the moisture returned from the HME is reduced, for example, due to the hygroscopicity of the HME material depending on the temperature. Therefore, the moisture returned to the air by the HME can be reduced by increasing the temperature of the air in the heated air delivery tube 4170, that is, the controller can compensate for the increased ambient humidity by increasing the temperature of the air in the heated air delivery tube 4170, thereby reducing the HME moisture return and balancing the moisture level inhaled by the patient. That is, the output of the HME can be controlled by the temperature of the incoming air.

[0387] One or more aspects of such an arrangement may improve patient comfort (e.g., warmer air, moister air, and / or less condensation) and / or may allow HME humidification to be more suitable for use in cold ambient temperatures. In addition, one or more aspects of such an arrangement may allow one variant of the HME to be suitable for a wide range of environmental conditions, e.g., a high-capacity HME model, thereby avoiding the need to select from more than one variant, reducing inventory, and / or improving patient comfort over a wider range.

[0388] It should be understood that the level of condensation within the patient interface and the temperature and humidity of the air inhaled by the patient may depend on the patient's preferences, for example, the patient may prefer at least some condensation levels. That is, some patients may be uncomfortable with the feeling of wetness, while other patients may tolerate a fairly wet nose. Moreover, the internal geometry of the patient interface and the sleeping position of the patient may affect where droplets from condensation may flow and accumulate, whether droplets splash out of the vent, or whether droplets drip back into the patient's nose and / or mouth, i.e., some droplets from condensation may not be destructive. One aspect of the present technology is to allow the condensation level and the temperature and humidity of the air inhaled by the patient to be controlled based on patient feedback, i.e., at least in part based on patient input or settings provided by the patient.

[0389] Figures 18 to 33 is a flow chart illustrating a control algorithm according to an alternative example of the present technology.

[0390] exist Fig.18 In the embodiment of the present invention, the patient sets a preferred or target gas temperature (e.g., in degrees), and feedback control is provided by the controller to adjust the power provided to the heated air delivery tube 4170 as needed to correct for any difference between the preferred gas temperature setting and the gas temperature measured by the gas temperature sensor 4178 provided to the heated air delivery tube 4170. For example, when the gas temperature measured by the gas temperature sensor 4178 is lower than the preferred gas temperature setting, the feedback control may increase the power to the heated air delivery tube 4170 to raise the gas temperature.

[0391] exist Fig.19, the target gas temperature is determined with reference to the ambient humidity. For example, the ambient humidity is measured by an ambient humidity sensor (such as provided to the RPT device), and the target gas temperature is set based on the measured ambient humidity, for example, a higher gas temperature is set at a higher humidity. The relationship between the measured ambient humidity and the set target gas temperature can be predetermined, such as via a lookup table. Feedback control is provided by the controller to adjust the power provided to the heated air delivery duct 4170 as needed to correct for any difference between the target gas temperature setting and the gas temperature measured by the gas temperature sensor 4178 provided to the heated air delivery duct 4170.

[0392] exist Fig. 20 In the embodiment of the present invention, the preferred gas temperature setting from the patient is used as a control input together with the measured ambient humidity. For example, a target gas temperature is set based on the preferred gas temperature setting from the patient and the measured ambient humidity. Feedback control is provided by the controller to adjust the power provided to the heated air delivery tube 4170 as needed to correct for any difference between the target gas temperature setting and the gas temperature measured by the gas temperature sensor 4178 provided to the heated air delivery tube 4170.

[0393] exist Fig.21 , a target gas temperature is determined with reference to the ambient temperature. The ambient temperature is measured by an ambient temperature sensor (e.g., provided to the RPT device), and the target gas temperature is set based on the measured ambient temperature, for example, setting a higher gas temperature at cooler ambient temperatures. The relationship between the measured ambient temperature and the set target gas temperature can be predetermined, for example, via a lookup table. Feedback control is provided by the controller to adjust the power provided to the heated air delivery tube 4170 as needed to correct for any difference between the target gas temperature setting and the gas temperature measured by the gas temperature sensor 4178 provided to the heated air delivery tube 4170.

[0394] exist Fig. 22 4170 . In the embodiment of the present invention, a preferred gas temperature setting from the patient is used as a control input along with the measured ambient temperature. For example, a target gas temperature is set based on the preferred gas temperature setting from the patient and the measured ambient temperature. In an example, the minimum gas temperature set by the patient can be increased in very cold environments based on the ambient temperature sensor. Feedback control is provided by the controller to adjust the power provided to the heated air delivery tube 4170 as needed to correct for any difference between the target gas temperature setting and the gas temperature measured by the gas temperature sensor 4178 provided to the heated air delivery tube 4170.

[0395] exist Fig.234170 , the ambient humidity is used as a control input along with the preferred gas temperature setting from the patient and the measured ambient temperature. For example, a target gas temperature is set based on the preferred gas temperature setting from the patient, the measured ambient temperature, and the measured ambient humidity. In an example, the gas temperature set by the patient can be adjusted based on the ambient temperature and / or the ambient humidity. Feedback control is provided by the controller to adjust the power provided to the heated air delivery tube 4170 as needed to correct for any difference between the target gas temperature setting and the gas temperature measured by the gas temperature sensor 4178 provided to the heated air delivery tube 4170.

[0396] exist Fig.24 , the target gas temperature is determined with reference to the gas flow. For example, the average gas flow is measured by a flow sensor (e.g., flow sensor 4095 provided to the RPT device), and the target gas temperature is set based on the measured gas flow. The relationship between the measured gas flow and the set target gas temperature can be predetermined, for example, via a lookup table. Feedback control is provided by the controller to adjust the power provided to the heated air delivery tube 4170 as needed to correct any difference between the target gas temperature setting and the gas temperature measured by the gas temperature sensor 4178 provided to the heated air delivery tube 4170.

[0397] exist Fig.25 In the embodiment of the present invention, the target gas temperature is determined with reference to the breathing rate and / or depth. For example, the breathing rate and / or depth are measured by a sensor, and the target gas temperature is set based on the measured breathing rate and / or depth. The relationship between the measured breathing rate and / or depth and the set target gas temperature can be predetermined by, for example, a lookup table. Feedback control is provided by the controller to adjust the power provided to the heated air delivery tube 4170 as needed to correct any difference between the target gas temperature setting and the gas temperature measured by the gas temperature sensor 4178 provided to the heated air delivery tube 4170.

[0398] exist Fig.26 In the preferred gas temperature setting from the patient, the ambient temperature, the gas flow rate, the respiratory rate and / or volume, and the ambient humidity are used as control inputs for the target gas temperature. For example, the target gas temperature is set based on the preferred gas temperature setting from the patient, the measured ambient temperature, the measured gas flow rate, the measured respiratory rate and / or volume, and the measured ambient humidity. In an example, the gas temperature set by the patient can be adjusted based on the ambient temperature, the gas flow rate, the respiratory rate and / or volume, and / or the ambient humidity. Feedback control is provided by the controller to adjust the power provided to the heated air delivery tube 4170 as needed to correct for any difference between the target gas temperature setting and the gas temperature measured by the gas temperature sensor 4178 provided to the heated air delivery tube 4170.

[0399] exist Fig. 27 4170 is used as a control input. In this example, the heated air delivery tube 4170 does not have a temperature sensor, and therefore no feedback control of the heated air delivery tube 4170 is provided. The patient sets a preferred heat level (e.g., low heat, medium heat, high heat) and the target power is set based on the heat setting. The relationship between the heat setting and the set target power can be predetermined, for example, via a lookup table.

[0400] exist Fig.28 , the target power to the heated air delivery duct 4170 is determined with reference to the ambient temperature. For example, the ambient temperature is measured by an ambient temperature sensor (such as provided to the RPT device), and the target power is set based on the measured ambient temperature, for example, a higher power is set at a cooler ambient temperature. The relationship between the measured ambient temperature and the set target power can be predetermined, such as via a lookup table.

[0401] exist Fig.29 In the embodiment of the present invention, the preferred thermal setting and the ambient temperature are used as control inputs. For example, the target power is set based on the preferred thermal setting and the measured ambient temperature. If the measured ambient temperature is considered insufficient, the power associated with the set thermal setting can be updated, for example, the power is adjusted higher for a colder ambient temperature.

[0402] exist Fig.30 In the embodiment of the present invention, the ambient humidity is used as a control input. For example, the ambient humidity is measured by an ambient humidity sensor (such as provided to the RPT device), and the target power is set based on the measured ambient humidity, for example, a higher power is set in a higher ambient humidity. The relationship between the measured ambient humidity and the set target power can be predetermined, for example, via a lookup table.

[0403] exist Fig.31 In the embodiment of the present invention, gas flow is used as a control input. For example, the average gas flow is measured by a flow sensor (e.g., flow sensor 4095 provided to the RPT device), and the target power is set based on the measured gas flow. The relationship between the measured gas flow and the set target power can be predetermined, for example, via a lookup table.

[0404] exist Fig.32 In the embodiment of the present invention, the breathing rate and / or depth are used as control inputs. For example, the breathing rate and / or depth are measured by a sensor, and the target power is set based on the measured breathing rate and / or depth. The relationship between the measured breathing rate and / or depth and the set target power can be predetermined by, for example, a lookup table.

[0405] exist Fig.33 In the embodiment of the present invention, the preferred thermal setting, the ambient temperature, the airflow, the respiratory rate and / or depth, and the ambient humidity are used as control inputs. For example, the target power is set based on the preferred thermal setting, the measured ambient temperature, the measured gas flow, the measured respiratory rate and / or depth, and the measured ambient humidity. If the measured ambient temperature, the measured gas flow, the measured respiratory rate and / or depth, and / or the measured ambient humidity are considered insufficient, the power associated with the set thermal setting can be updated, for example, the power is adjusted higher for a colder ambient temperature and a higher ambient humidity.

[0406] In an alternative example, fixed power may be provided to the heated air delivery tube 4170. While such an arrangement would not require temperature sensing, such an arrangement provides poor regulation, e.g., for patient comfort.

[0407] In an alternative example, the HME may be heated in an alternative manner rather than via a heated air delivery tube. For example, a heater may be provided to the patient interface, e.g., along a plenum of the patient interface, to heat the patient interface and the HME. In another example, a heater may be provided to the HME, e.g., to heat the HME directly. One or more of the above-described control algorithms for controlling power to the heated air delivery tube may also be applicable to controlling power to a heater provided to the HME. In another example, a high heat capacity material may be provided in the HME to increase passive heat storage.

[0408] In the optional example, Fig.16 As shown, the HME can be used in conjunction with a heated flow-through humidifier. Fig.16 The CPAP system in includes an RPT device 4000 with an integrated humidifier, which includes a water reservoir 5110, a patient interface 3000, an adapter 6000 including a HME 6500, and a heated air delivery tube 4170. The humidifier increases the ambient temperature and humidity and the HME further captures moisture from the patient. When the HME is detected, the humidifier output can be updated.

[0409] 5.7 Humidifier

[0410] 5.7.1 Humidifier Overview

[0411] In one form of the present technology, a humidifier 5000 (e.g., Figure 5C ) to change the absolute humidity of the air or gas for delivery to the patient relative to the ambient air. Typically, the humidifier 5000 is used to increase the absolute humidity of the air flow and increase the temperature of the air flow (relative to the ambient air) before delivery to the patient's airway.

[0412] The humidifier 5000 may include a humidifier reservoir 5110, a humidifier inlet for receiving an air flow, and a humidifier outlet for delivering a humidified air flow. The humidifier 5000 may also include a humidifier base, which may be adapted to receive the humidifier reservoir 5110 and include a heating element.

[0413] 5.7.2 Humidifier components

[0414] 5.7.2.1 Water storage tank

[0415] According to one arrangement, the humidifier 5000 may include a water reservoir 5110 configured to hold or retain a liquid (e.g., water) volume to be evaporated for humidifying the air flow. The water reservoir 5110 may be configured to hold a predetermined maximum water volume so as to provide adequate humidification for at least the duration of a respiratory therapy session, such as one night of sleep. Typically, the reservoir 5110 is configured to hold several hundred milliliters of water, for example, 300 milliliters (ml), 325 ml, 350 ml, or 400 ml. In other forms, the humidifier 5000 may be configured to receive a water supply from an external water source such as a building's water supply system.

[0416] According to one aspect, the water reservoir 5110 is configured to add humidity to the air flow from the RPT device 4000 as the air flow travels therethrough. In one form, the water reservoir 5110 may be configured to encourage the air flow to travel in a tortuous path through the reservoir 5110 while in contact with the volume of water therein.

[0417] According to one form, the reservoir 5110 may be removed from the humidifier 5000, for example in a lateral direction.

[0418] The reservoir 5110 may also be configured to prevent liquid from flowing out of it, such as through any holes and / or between its subcomponents, such as when the reservoir 5110 is displaced and / or rotated from its normal working orientation. Since the air flow to be humidified by the humidifier 5000 is generally pressurized, the reservoir 5110 may also be configured to avoid loss of pneumatic pressure through leakage and / or flow resistance.

[0419] 5.7.2.2 Conductive part

[0420] According to one arrangement, the reservoir 5110 includes a conductive portion that is configured to allow efficient transfer of heat from the heating element to the liquid content in the reservoir 5110. In one form, the conductive portion may be arranged as a plate, but other shapes may also be equally suitable. All or part of the conductive portion may be made of a thermally conductive material, such as aluminum (e.g., having a thickness of about 2 mm, such as 1 mm, 1.5 mm, 2.5 mm or 3 mm), another thermally conductive metal or some plastic. In some cases, suitable thermal conductivity may be achieved with a material of appropriate geometry having a lower conductivity.

[0421] 5.7.2.3 Humidifier reservoir dock

[0422] In one form, the humidifier 5000 may include a humidifier reservoir base configured to receive the humidifier reservoir 5110. In some arrangements, the humidifier reservoir base may include a locking feature, such as a locking lever configured to retain the reservoir 5110 in the humidifier reservoir base.

[0423] 5.7.2.4 Water level indicator

[0424] The humidifier reservoir 5110 may include a water level indicator. In some forms, the water level indicator may provide a user (such as the patient 1000 or a caregiver) with one or more indications of the amount of water volume in the humidifier reservoir 5110. The one or more indications provided by the water level indicator may include an indication of a maximum predetermined volume of water, any portion thereof, such as 25%, 50%, 75%, or a volume such as 200 ml, 300 ml, or 400 ml.

[0425] 5.7.2.5 Humidifier converter

[0426] The humidifier 5000 may include one or more humidifier transducers (sensors) 5210 instead of or in addition to the transducers 4270 described above. Figure 5G As shown, the humidifier converter 5210 may include one or more of an air pressure sensor 5212, an air flow converter 5214, a temperature sensor 5216, or a humidity sensor 5218. The humidifier converter 5210 may generate one or more output signals that may be communicated to a controller, such as the central controller 4230 and / or the humidifier controller 5250. In some forms, the humidifier converter may be provided externally to the humidifier 5000 (such as in the air circuit 4170) when communicating the output signals to the controller.

[0427] 5.7.2.5.1 Pressure converter

[0428] In lieu of or in addition to the pressure sensor 4272 provided in the RPT device 4000 , one or more pressure transducers 5212 may be provided to the humidifier 5000 .

[0429] 5.7.2.5.2 Air flow converter

[0430] In lieu of or in addition to the flow sensor 4274 provided in the RPT device 4000 , one or more flow transducers 5214 may be provided to the humidifier 5000 .

[0431] 5.7.2.5.3 Temperature converter

[0432] The humidifier 5000 may include one or more temperature transducers 5216. The one or more temperature transducers 5216 may be configured to measure one or more temperatures, such as the temperature of the heating element 5240 and / or the air flow downstream of the humidifier outlet. In some forms, the humidifier 5000 may further include a temperature sensor 5216 for detecting the ambient air temperature.

[0433] 5.7.2.5.4 Humidity converter

[0434] In some forms, the humidifier 5000 may include one or more humidity sensors 5218 that detect the humidity of a gas (such as ambient air). In some forms, the humidity sensor 5218 may be positioned toward the humidifier outlet to measure the humidity of the gas delivered from the humidifier 5000. The humidity sensor may be an absolute humidity sensor or a relative humidity sensor.

[0435] 5.7.2.6 Heating elements

[0436] In some cases, a heating element 5240 can be provided to the humidifier 5000 to provide heat input to one or more of the water volumes in the humidifier reservoir 5110 and / or to the air flow. The heating element 5240 can include a heat generating component, such as a resistive electric heating rail. A suitable example of a heating element 5240 is a layered heating element, such as the layered heating element described in PCT Patent Application Publication No. WO 2012 / 171072, which is incorporated herein by reference in its entirety.

[0437] In some forms, the heating element 5240 may be disposed in the humidifier base, where heat may be provided to the humidifier reservoir 5110 primarily by conduction.

[0438] 5.7.2.7 Humidifier controller

[0439] According to one arrangement of the present technology, Figure 5GThe humidifier 5000 shown in FIG. 5 may include a humidifier controller 5250. In one form, the humidifier controller 5250 may be part of the central controller 4230. In another form, the humidifier controller 5250 may be a separate controller that may communicate with the central controller 4230.

[0440] In one form, the humidifier controller 5250 may receive as input, for example, measurements of characteristics of the air flow, water flow (such as temperature, humidity, pressure and / or flow) in the reservoir 5110 and / or the humidifier 5000. The humidifier controller 5250 may also be configured to execute or implement a humidifier algorithm and / or deliver one or more output signals.

[0441] like Figure 5G As shown in , the humidifier controller 5250 may include one or more controllers, such as a central humidifier controller 5251, a heated air circuit controller 5254 configured to control the temperature of the heated air circuit 4171, and / or a heating element controller 5252 configured to control the temperature of the heating element 5240.

[0442] 5.8 Respiratory waveform

[0443] Figure 4 A typical breathing waveform model of a person sleeping is shown. The horizontal axis is time and the vertical axis is respiratory flow. Although the parameter values ​​may vary, a typical breath may have the following approximate values: tidal volume (Vt) 0.5 L, inspiratory time (Ti) 1.6 s, peak inspiratory flow (Qpeak) 0.4 L / s, expiratory time (Te) 2.4 s, peak expiratory flow (Qpeak) -0.5 L / s. The total duration of breathing (Ttot) is about 4 s. People usually breathe at a respiratory rate of about 15 breaths / minute (BPM), with a ventilation volume Vent of about 7.5 L / min. The typical duty cycle (ratio of Ti to Ttot) is about 40%.

[0444] 5.9 Terminology

[0445] For purposes of this technical disclosure, in certain forms of the technology, one or more of the following definitions may apply. In other forms of the technology, alternative definitions may apply.

[0446] 5.9.1 General terms

[0447] Air: In some forms of the present technology, air may be considered to mean atmospheric air, and in other forms of the present technology, air may be considered to mean some other combination of breathable gases, such as atmospheric air enriched with oxygen.

[0448] Environment: In certain forms of the present technology, the term environment can have the following meanings: (i) external to the treatment system or patient, and (ii) directly surrounding the treatment system or patient.

[0449] For example, the ambient humidity relative to the humidifier may be the humidity of the air directly surrounding the humidifier, such as the humidity within the room that the patient is sleeping in. This ambient humidity may be different from the humidity outside the room that the patient is sleeping in.

[0450] In another example, ambient pressure can be the pressure immediately surrounding or external to the body.

[0451] In some forms, ambient (e.g., acoustic) noise may be considered to be the background noise level in the room the patient is in, in addition to noise generated, for example, by the RPT device or from a mask or patient interface. Ambient noise may be generated by sound sources outside the room.

[0452] Automatic Positive Airway Pressure (APAP) Therapy: CPAP therapy in which the therapy pressure is automatically adjustable between a minimum and a maximum limit, e.g., with each breath, depending on whether there is an indication of a SDB event.

[0453] Continuous Positive Airway Pressure (CPAP) therapy: A breathing pressure therapy in which the therapy pressure can be approximately constant throughout the patient's breathing cycle. In some forms, the pressure at the airway entrance will be slightly higher during exhalation and slightly lower during inspiration. In some forms, the pressure will vary between different breathing cycles of the patient, for example, increasing in response to detecting an indication of partial upper airway obstruction, and decreasing in the absence of an indication of partial upper airway obstruction.

[0454] Flow: Volume (or mass) of air delivered per unit time. Flow may refer to an instantaneous quantity. In some cases, reference to flow will be to a scalar quantity, i.e. a quantity having only magnitude. In other cases, reference to flow will be to a vector quantity, i.e. a quantity having both magnitude and direction. Flow may be given by the symbol Q. 'Flow' is sometimes simply abbreviated to 'flow' or 'airflow'.

[0455] In the example of a patient breathing, the flow 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. The total flow, Qt, is the air flow leaving the RPT device. The ventilation flow, Qv, is the air flow leaving the vent to allow for flushing of exhaled gases. The leakage flow, Ql, is the leakage flow from the patient interface system. The respiratory flow, Qr, is the air flow received into the patient's breathing system.

[0456] Humidifier: The term humidifier is considered to refer to a humidifying device that is constructed and arranged or configured to have a physical structure capable of providing therapeutically beneficial amounts of water (H2O) vapor to an air flow to improve the medical respiratory condition of a patient.

[0457] Leakage: The word leakage is considered to be undesirable air flow. In one example, leakage may occur due to an incomplete seal between the mask and the patient's face. In another example, leakage may occur in the swivel elbow to the surrounding environment.

[0458] Noise, conducted (acoustic): Conducted noise in this document refers to the noise brought to the patient through the pneumatic path (such as 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.

[0459] Noise, radiated (acoustic): Radiated noise in this document refers to the noise that is brought to the patient through the ambient air. In one form, radiated noise can be quantified by measuring the sound power / pressure level of the object in question according to ISO 3744.

[0460] Ventilation noise in this context refers to the noise generated by the flow of air through any vent, such as a vent in a patient interface.

[0461] Patient: A person, whether or not they have a respiratory illness.

[0462] Pressure: Force per unit area. Pressure can be expressed in a range of units, including cmH2O, gf / cm 2 and hectopascal. 1cmH2O is equal to 1g-f / cm 2 , which is approximately 0.98 hectopascals. In this specification, unless otherwise specified, pressure is given in cmH2O.

[0463] The pressure in the patient interface is given the symbol Pm, while the therapy pressure is given the symbol Pt, which represents the target value to be achieved by the mask pressure Pm at the current moment.

[0464] Respiratory Pressure Therapy (RPT): The application of a supply of air to the airway entrance at a therapeutic pressure that is typically positive relative to atmosphere.

[0465] Ventilator: A mechanical device that provides pressure support to a patient to perform some or all of the work of breathing.

[0466] 5.9.1.1 Materials

[0467] Silicone or Silicone Elastomer: Synthetic rubber. In this specification, references to silicone refer to liquid silicone rubber (LSR) or compression molded silicone rubber (CMSR). One form of commercially available LSR is SILASTIC (included in the range of products sold under this trademark), which is manufactured by Dow Corning. Another manufacturer of LSR is Wacker. Unless otherwise specified to the contrary, exemplary forms of LSR have a Shore A (or Type A) indentation hardness in the range of about 35 to about 45 as measured using ASTM D2240.

[0468] Polycarbonate: A thermoplastic polymer of bisphenol A carbonate.

[0469] 5.9.1.2 Mechanical properties

[0470] Elasticity: The ability of a material to absorb energy when it deforms elastically and release that energy when it deflates.

[0471] Resilient: Releases substantially all of its energy when deflated. Includes some silicones and thermoplastic elastomers.

[0472] Hardness: The ability of a material to resist deformation of itself (e.g., as described by Young's modulus, or the indentation hardness scale measured for a standard sample size).

[0473] 'Soft' materials may include silicone or thermoplastic elastomers (TPE), and may deform easily, for example under finger pressure.

[0474] 'Hard' materials may include polycarbonate, polypropylene, steel or aluminium, and may not deform easily, for example, under finger pressure.

[0475] Stiffness (or rigidity) of a structure or component: The ability of a structure or component to resist deformation in response to an applied load. The load can be a force or a moment, such as compression, tension, bending or torsion. A structure or component can provide different resistance in different directions.

[0476] Floppy structure or component: A structure or component that will change shape, e.g. bend, when made to support its own weight for a relatively short period of time, such as 1 second.

[0477] 'Rigid' structure or component: A structure or component that will not substantially change shape when subjected to loads typically encountered in use. One example of this use may be to place and maintain a patient interface in sealing relationship with an entrance to a patient's airway, for example under a load of about 20 to 30 cmH2O pressure.

[0478] As an example, an I-beam may include a different bending stiffness (resistance to bending loads) in a first direction compared to a second, orthogonal direction. In another example, a structure or component is floppy in a first direction and rigid in a second direction.

[0479] 5.9.2 Breathing cycle

[0480] Apnea: According to some definitions, an apnea is considered to occur when flow drops below a predetermined threshold for a sustained period of time (e.g., 10 seconds). Obstructive apnea is considered to occur when some obstruction of the airway does not allow air to flow despite the patient's efforts. Central apnea is considered to occur when apnea is detected due to a decrease or absence of respiratory effort despite a patent airway. Mixed apnea is considered to occur when a decrease or absence of respiratory effort occurs simultaneously with an obstructed airway.

[0481] Respiratory rate: The rate at which a patient breathes spontaneously, usually measured in breaths per minute.

[0482] Duty cycle: the ratio of inspiratory time Ti to total breathing time Ttot.

[0483] Effort (breathing): The work done by a spontaneous breather in an attempt to breathe.

[0484] Expiratory portion of the respiratory cycle: the period from the start of expiratory flow to the start of inspiratory flow.

[0485] Flow Limitation: Flow limitation is to be considered a state in the patient's breathing where an increase in the patient's effort does not result in a corresponding increase in flow. Where flow limitation occurs during the inspiratory portion of the breathing cycle, it may be described as inspiratory flow limitation. Where flow limitation occurs during the expiratory portion of the breathing cycle, it may be described as expiratory flow limitation.

[0486] Types of flow-limited inspiratory waveforms:

[0487] (i) Flattened: Having a rise followed by a relatively flat portion and then a fall.

[0488] (ii) M-shape: has two local peaks, one at the leading edge and one at the trailing edge, with a relatively flat portion between the two peaks.

[0489] (iii) Chair shape: has a single local peak at the leading edge followed by a relatively flat section.

[0490] (iv) Reverse chair shape: has a relatively flat section followed by a single local peak located at the trailing edge.

[0491] Hypopnea: According to some definitions, hypopnea is considered a decrease in flow, but not a cessation of flow. In one form, hypopnea is considered to occur when flow decreases below a threshold for a sustained period of time. Central hypopnea is considered to occur when hypopnea is detected due to a decrease in respiratory effort. In one form in adults, any of the following may be considered hypopnea:

[0492] (i) The patient's respiration decreases by 30% for at least 10 seconds with an associated 4% desaturation; or

[0493] (ii) The patient has a decrease in breathing (but less than 50%) lasting at least 10 seconds with an associated desaturation or arousal of at least 3%.

[0494] Hyperpnea: An increase in flow to a level above normal flow.

[0495] Inspiratory portion of the respiratory cycle: The period from the start of inspiratory flow to the start of expiratory flow is considered the inspiratory portion of the respiratory cycle.

[0496]

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

[0497] Positive End Expiratory Pressure (PEEP): The pressure above atmospheric pressure that exists in the lungs at the end of exhalation.

[0498] Peak Flow (Q Peak): The maximum value of the flow during the inspiratory portion of the respiratory flow waveform.

[0499] Respiratory flow, patient air flow, respiratory air flow (Qr): These terms may be understood to refer to the RPT device's estimate of respiratory flow, as opposed to "true respiratory flow" or "real respiratory flow", which is the actual respiratory flow experienced by the patient, typically expressed in liters per minute.

[0500] Tidal volume (Vt): The volume of air inhaled or exhaled during normal breathing when no additional effort is exerted. In principle, the inspiratory volume Vi (the volume of air inhaled) is equal to the expiratory volume Ve (the volume of air exhaled), so a single tidal volume Vt can be defined to be equal to either volume. In practice, the tidal volume Vt is estimated as some combination of the inspiratory volume Vi and the expiratory volume Ve, such as an average.

[0501] (Inspiratory) Time (Ti): Duration of the inspiratory portion of the respiratory flow waveform.

[0502] (Expiratory) Time (Te): Duration of the expiratory portion of the respiratory flow waveform.

[0503] (Total) Time (Ttotal): The total duration between the start of the inspiratory portion of a respiratory flow waveform and the start of the inspiratory portion of the subsequent respiratory flow waveform.

[0504] Typical recent ventilation: The ventilation value Vent around which recent values ​​on some predetermined time scale tend to cluster, that is, a measure of the central tendency of recent values ​​of ventilation.

[0505] Upper airway obstruction (UAO): includes partial and total upper airway obstruction. This can be associated with a state of flow limitation, where flow increases only slightly or can even decrease as the pressure difference across the upper airway increases (Starling impedance behavior).

[0506] Ventilation (Vent): A measurement of the flow of gases exchanged by a patient's respiratory system. Measurements of ventilation may include one or both of inspiratory and expiratory flow (per unit time). When expressed as a volume per minute, this quantity is often referred to as "minute ventilation". Minute ventilation is sometimes given simply as volume, and is understood to be the volume per minute.

[0507] 5.9.3 Ventilation

[0508] Adaptive servo ventilator (ASV): A servo ventilator with a variable rather than fixed target ventilation. The variable target ventilation may be derived from some characteristics of the patient, such as the patient's breathing characteristics.

[0509] Backup Rate: A parameter of a ventilator that determines the minimum respiratory rate (usually measured in breaths per minute) that the ventilator will deliver to the patient if not triggered by a spontaneous respiratory effort.

[0510] Cyclic: The termination of the inspiratory phase of a ventilator. When a ventilator is delivering a breath to a spontaneously breathing patient, at the end of the inspiratory portion of the respiratory cycle, the ventilator is considered to cycle to stop delivering a breath.

[0511] Expiratory Positive Airway Pressure (EPAP): The base pressure to which the intra-breath varying pressures are added to produce the desired mask pressure that the ventilator will attempt to achieve at a given time.

[0512] End-expiratory pressure (EEP): The desired mask pressure that the ventilator attempts to achieve at the end of the expiratory portion. If the pressure waveform template Π(Φ) is zero at the end of exhalation, i.e., Π(Φ) = 0 when Φ = 1, then EEP is equal to EPAP.

[0513] Inspiratory Positive Airway Pressure (IPAP): The maximum desired mask pressure that the ventilator attempts to achieve during the inspiratory portion of a breath.

[0514] Pressure Support: A number that indicates the increase in pressure during ventilator inspiration over the pressure during ventilator expiration, and usually means the difference in pressure between the maximum during inspiration and the base pressure (e.g., PS = IPAP - EPAP). In some cases, pressure support means the difference that the ventilator aims to achieve, rather than the difference that is actually achieved.

[0515] Servomotor: A ventilator that measures patient ventilation, has a target ventilation and adjusts the level of pressure support to bring the patient's ventilation to the target ventilation.

[0516] Spontaneous / Timed (S / T): A mode of a ventilator or other device that attempts to detect the onset of a breath in a spontaneously breathing patient. However, if the device cannot detect a breath within a predetermined period of time, the device will automatically initiate the delivery of a breath.

[0517] Swing: A term equivalent to pressure support.

[0518] Triggered: When the ventilator delivers breathed air to a spontaneously breathing patient, it is considered to be triggered at the beginning of the breath portion of the breathing cycle through the patient's effort.

[0519] 5.9.3.1 Anatomy of the respiratory system

[0520] Diaphragm: A sheet of muscle that extends across the base of the rib cage. The diaphragm separates the thoracic cavity, which contains the heart, lungs, and ribs, from the abdominal cavity. As the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn into the lungs.

[0521] Larynx: The larynx or voice box houses the vocal cords and connects the lower part of the pharynx (hypopharynx) to the trachea.

[0522] Lung: The respiratory organ of humans. The conducting zone of the lungs contains the trachea, bronchi, bronchioles, and terminal bronchioles. The respiratory zone contains the respiratory bronchioles, alveolar ducts, and alveoli.

[0523] Nasal Cavity: The nasal cavity (or nasal fossa) is a large air-filled space above and behind the nose in the middle of the face. The nasal cavity is divided into two parts by a vertical wing called the nasal septum. On the sides of the nasal cavity are three horizontal branches called the nasal conchae (singular "concha") or turbinates. The front of the nasal cavity is the nose, while the back joins into the nasopharynx via the internal nostrils.

[0524] Pharynx: The part of the throat located just below (under) the nasal cavity and above the esophagus and larynx. The pharynx is conventionally divided into three sections: the nasopharynx (epipharynx) (nasal portion of the pharynx), the oropharynx (mesopharynx) (oral portion of the pharynx), and the hypopharynx (hypopharynx).

[0525] 5.9.4 Patient Interface

[0526] Anti-Asphyxia Valve (AAV): A component or subcomponent of a mask system that reduces the risk of excessive CO2 rebreathing by the patient by opening to atmosphere in a fail-safe manner.

[0527] Elbow: An elbow is an example of a structure that directs the axis of an air flow to change direction through a certain angle. In one form, the angle can be about 90 degrees. In another form, the angle can be greater or less than 90 degrees. The elbow can have a cross-section that is approximately circular. In another form, the elbow can have an elliptical or rectangular cross-section. In some forms, the elbow can be rotated relative to a mating component, for example, through about 360 degrees. In some forms, the elbow can be removable from a mating component, such as by a snap connection. In some forms, the elbow can be assembled to the mating component during the manufacturing process with a disposable snap, but cannot be removed by the patient.

[0528] Frame: A frame will be considered to mean the mask structure that carries the tensile load between two or more connection points to the headgear. A mask frame may be a non-airtight load-bearing structure in a mask. However, some forms of mask frames may also be airtight.

[0529] Headgear: A headgear will be considered to mean a form of positioning and stabilizing structure designed for use on the head. For example, a headgear may include a collection of one or more support bars, straps, and reinforcement bars configured to position and maintain a patient interface in position on a patient's face for delivery of respiratory therapy. Some straps are formed of soft, flexible, resilient materials, such as laminate composites of foam and textiles.

[0530] Film: A film shall be taken to mean a typically thin element which preferably has substantially no resistance to bending, but has resistance to stretching.

[0531] Plenum: A mask plenum will be taken to mean a portion of the patient interface having walls at least partially enclosing a volume of space which, in use, has air pressurized therein to above atmospheric pressure. The housing may form part of the wall of the mask plenum.

[0532] Seal: can be a noun indicating structure ("seal") or a verb indicating action ("to seal"). Two elements can be constructed and / or arranged to seal between them or achieve a "seal" between them without the need for a separate "sealing" element itself.

[0533] Shell: Shell will be taken to mean a curved and relatively thin structure having a bendable, stretchable and compressible stiffness. For example, a curved structural wall of a mask may be a shell. In some forms, the shell may be multi-faceted. In some forms, the shell may be airtight. In some forms, the shell may not be airtight.

[0534] Reinforcement: A reinforcement will be taken to mean a structural component designed to increase the bending resistance of another component in at least one direction.

[0535] Braces: Braces will be considered to be structural components designed to increase the compression resistance of another component in at least one direction.

[0536] Swivel (n): A subassembly of a component configured to rotate about a common axis, preferably independently, 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 of less than 360 degrees. When used in the context of an air delivery conduit, the subassembly of the component preferably comprises a pair of matching cylindrical conduits. There may be little or no air flow leakage from the swivel when in use.

[0537] Tie (noun): A structure designed to resist tension.

[0538] Vent: (noun): A structure that allows air flow from the interior of a mask or duct to ambient air, e.g., to allow effective flushing of exhaled gases. For example, clinically effective flushing may involve a flow rate of about 10 liters per minute to about 100 liters per minute, depending on the mask design and the treatment pressure.

[0539] 5.9.5 Shape of the structure

[0540] Products according to the present technology may include one or more three-dimensional mechanical structures, such as a mask cushion or a thruster. The three-dimensional structures may be combined by two-dimensional surfaces. These surfaces may be distinguished using markings to describe the relative surface orientation, position, function, or some other feature. For example, a structure may include one or more of a front surface, a rear surface, an inner surface, and an outer surface. In another example, a seal-forming structure may include a face-contacting (e.g., outer) surface and a separate non-face-contacting (e.g., underside or inner) surface. In another example, a structure may include a first surface and a second surface.

[0541] To help describe the shape of three-dimensional structures and surfaces, we first consider a cross section through a point p on the surface of the structure. FIG. 3B to FIG. 3F , which show examples of cross sections at a point p on the surface and the resulting plane curve. FIG. 3B to FIG. 3F The outward normal vector at point p is also shown. The outward normal vector at point p points away from the surface. In some examples, the surface is described from the point of view of an imaginary person standing upright on the surface.

[0542] 5.9.5.1 Curvature in one dimension

[0543] The curvature of a plane curve at p can be described as having a sign (eg, positive, negative) and a magnitude (eg, the inverse of the radius of a circle that touches the curve only at p).

[0544] Positive curvature: If the curve at p turns toward the outward normal, then the curvature at that point will be positive (if the imaginary person were to leave that point p, they would have to walk uphill). Figure 3B (and Figure 3C Compared with the relatively large positive curvature) and Figure 3C (and Figure 3B Such curves are often called concave.

[0545] Zero curvature: If the curve at point p is a straight line, then the curvature will be zero (if the imaginary person leaves point p, they can walk horizontally without going up or down). Figure 3D .

[0546] Negative curvature: If the curve at point p turns away from the outward normal, then the curvature in that direction at that point will be negative (if the imaginary person were to leave that point p, they would have to go downhill). Figure 3E (and Figure 3F Compared to the relatively small negative curvature) and Figure 3F (and Figure 3E Such curves are often called convex.

[0547] 5.9.5.2 Curvature of a Two-Dimensional Surface

[0548] A description of a shape at a given point on a two-dimensional surface according to the present technology may include multiple normal cross sections. Multiple cross sections may cut the surface in a plane that includes the outward normal ("normal plane"), and each cross section may be taken in a different direction. Each cross section produces a planar curve with a corresponding curvature. The different curvatures at the point may have the same sign or different signs. Each curvature at the point has a magnitude, such as a relatively small magnitude. FIG. 3B to FIG. 3F The plane curve in can be an example of such multiple cross sections at specific points.

[0549] Principal curvatures and principal directions: The directions of the normal planes where the curvature of the curve takes its maximum and minimum values ​​are called principal directions. FIG. 3B to FIG. 3F In the example of Figure 3B and the minimum value appears at Figure 3F Therefore Figure 3B and Figure 3F is the cross section in the principal direction. The principal curvature at p is the curvature in the principal direction.

[0550] Region of a surface: A connected set of points on a surface. The points in a region can have similar characteristics, such as curvature or sign.

[0551] Saddle region: A region where at each point the principal curvatures have opposite signs, ie one sign is positive and the other sign is negative (depending on the direction the imagined individual is turning, they can be walking up or down).

[0552] Dome region: The region where at every point the principal curvatures have the same sign, e.g. two positive ("concave dome") or two negative ("convex dome").

[0553] Cylindrical region: A region where one of the principal curvatures is zero (or is zero, for example, within manufacturing tolerances) and the other principal curvature is non-zero.

[0554] Planar region: A surface region where both principal curvatures are zero (or are zero within manufacturing tolerances, for example).

[0555] Edge of a surface: The boundary or limit of a surface or area.

[0556] Path: In some forms of the present technology, a 'path' will be taken to mean a path in a mathematical-topological sense, e.g. a continuous spatial curve from f(0) to f(1) on a surface. In some forms of the present technology, a 'path' may be described as a route or course comprising, e.g., a set of points on a surface. (An imagined individual's path is one in which they walk on a surface and is similar to a garden path).

[0557] Path length: In some forms of the present technology, 'path length' will mean the distance along the surface from f(0) to f(1), i.e. the distance along a path on the surface. There may be more than one path between two points on the surface and such paths may have different path lengths. (The path length of an imaginary individual would be the distance they walked along the path on the surface).

[0558] Straight-line distance: Straight-line distance is the distance between two points on a surface, but regardless of the surface. In a planar region, there can be a path on the surface that has the same path length as the straight-line distance between two points on the surface. In a non-planar surface, there can be no path that has the same path length as the straight-line distance between two points. (For an imaginary individual, straight-line distance would correspond to the distance as a 'straight line'.)

[0559] 5.9.5.3 Space curve

[0560] Space curves: Unlike plane curves, space curves do not have to lie in any particular plane. Space curves can be closed, i.e. have no endpoints. Space curves can be thought of as one-dimensional slices of three-dimensional space. An imaginary individual walking on a DNA helix walks along a space curve. A typical human left ear consists of a helix, i.e., the left helix, see Figure 3Q The typical human right ear includes a helix, the right helix, cf. Figure 3R . Figure 3S A right-handed spiral is shown. The edge of a structure, such as the edge of a membrane or propeller, can follow a space curve. In general, a space curve can be described by the curvature and twist at each point on the space curve. Twist is a measure of how the curve departs from the surface. Twist has a sign and a magnitude. The twist at a point on a space curve can be characterized with reference to the tangent, normal, and binormal vectors at that point.

[0561] Tangent unit vector (or unit tangent vector): For each point on a curve, the vector at that point indicates the direction from that point as well as the amount. The tangent unit vector is a unit vector pointed in the same direction as the curve at that point. If an imaginary individual were flying along the curve and stopped at a particular point, the direction of the tangent vector is the direction it would be traveling.

[0562] Unit Normal Vector: As the imaginary individual moves along the curve, this tangent vector itself changes. The unit vector pointing in the same direction that the tangent vector is changing is called the unit principal normal vector. It is perpendicular to the tangent vector.

[0563] Binormal unit vector: The binormal unit vector is perpendicular to the tangent vector and the principal normal vector. Its direction can be determined by the right-hand rule (see, e.g. Figure 3P ) or alternatively by the left-hand rule ( Fig.3O ) to determine.

[0564] Osculating plane: The plane containing the unit tangent vector and the unit principal normal vector. Fig.3O and Figure 3P .

[0565] Torsion of a space curve: The torsion at a point on a space curve is the amount of rate of change of the binormal vector at that point. It measures how much the curve deviates from the osculating plane. A space curve that lies on a plane has zero torsion. A space curve that deviates from the osculating plane by a relatively small amount will have a relatively small amount of torsion (e.g., a slightly tilted spiral path). A space curve that deviates from the osculating plane by a relatively large amount will have a relatively large amount of torsion (e.g., a sharply tilted spiral path). Figure 3S , although T2>T1, in Figure 3S The number of twists near the top helical coil is greater than Figure 3S The number of twists in the bottom helical coil.

[0566] refer to Figure 3P According to the right-hand rule, a space curve that turns in the direction of the right-hand binormal can be considered to have right-hand positive twist (for example, Figure 3S A space curve that deviates away from the right-handed binormal direction can be considered to have right-handed negative twist (e.g., a left-handed helix).

[0567] Similarly and referring to the left-hand rule (see Fig.3O ), a space curve that turns in the direction of the left-handed binormal can be considered to have left-handed positive twist (e.g., a left-handed helix). Thus, left-handed positive twist is equivalent to right-handed negative twist. Figure 3T .

[0568] 5.9.5.4 Holes

[0569] A surface may have one-dimensional pores, for example pores defined by a plane curve or by a space curve. A thin structure (e.g., a membrane) having pores may be described as having one-dimensional pores. For example, see Fig. 3I A one-dimensional hole in the surface of the structure shown in , which is defined by a plane curve.

[0570] The structure may have a two-dimensional aperture, such as an aperture defined by a surface. For example, an inflatable tire has a two-dimensional aperture defined by the inner surface of the tire. In another example, a bladder having a cavity for air or gel has a two-dimensional aperture. See, e.g. Figure 3L Cushions and Figure 3M and Figure 3N An exemplary cross section through a catheter is shown, wherein the inner surface defining the two-dimensional hole is shown. In another example, the catheter can include a one-dimensional hole (e.g., at its inlet or at its outlet) and a two-dimensional hole defined by the inner surface of the catheter. See also Figure 3K The two-dimensional pores of the structure shown are defined by the surfaces shown.

[0571] 5.10 Other notes

[0572] Unless the context clearly indicates and provides a numerical range, it is understood that each intervening value between the upper and lower limits of the range, to one-tenth of the unit of the lower limit, and any other stated or intervening value in the stated range are broadly included in the present technology. The upper and lower limits of these intermediate ranges may be independently included in the intermediate ranges and are also included in the present technology, but are subject to any explicitly excluded limits in the stated ranges. In the case where the stated range includes one or both of the stated limits, the present technology also includes ranges excluding either or both of those included limits.

[0573] Furthermore, where a value or values ​​are described herein for implementation as part of the present technology, it should be understood that such values ​​may be approximate unless otherwise indicated and that such values ​​may be used to any appropriate number of significant digits to the extent that practical technical implementations may permit or require it.

[0574] 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 the technology belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the technology, a limited number of representative methods and materials are described herein.

[0575] When a specific material is identified for use in constructing a component, obvious alternative materials having similar properties are substituted therefor. In addition, unless otherwise specified, any and all components described herein are understood to be capable of being manufactured and thus may be manufactured together or separately.

[0576] It must be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural equivalents unless the context clearly dictates otherwise.

[0577] All publications mentioned herein are incorporated herein in their entirety by reference, to disclose and describe methods and / or materials as the subject of those publications. Providing the publications discussed herein is only for the disclosures before the filing date of the present application. Anything herein should not be construed as admitting that the present technology is not entitled to the priority of these publications due to previous inventions. In addition, the publication date provided may be different from the actual publication date, which may need to be confirmed separately.

[0578] The terms "comprises" and "comprising" should be understood to refer to each element, component or step in a non-exclusive manner, indicating that the marked elements, components or steps may be present or utilized, or in combination with other elements, components or steps that are not marked.

[0579] The subject headings used in the detailed description are for the convenience of the reader and should not be used to limit the subject matter that can be found in the entire disclosure or claims. The subject headings should not be used to interpret the scope of the claims or the limitations of the claims.

[0580] Although the technology herein has been described with reference to specific examples, it should be understood that these examples only illustrate the principles and applications of the technology. In some cases, terms and symbols may mean specific details that are not required for practicing the technology. For example, although the terms "first" and "second" may be used, unless otherwise specified, they are not intended to indicate any order, but can be used to distinguish different elements. In addition, although the process steps in the method can be described or shown in order, such order is not necessary. Those skilled in the art will recognize that such an order can be modified and / or various aspects thereof can be performed simultaneously or even synchronously.

[0581] It is therefore to be understood that numerous modifications may be made to the illustrative examples and that other arrangements may be devised without departing from the spirit and scope of the present technology.

[0582] 5.11 Reference Symbols List

[0583]

[0584]

[0585]

Claims

1. A CPAP system for providing positive pressure air for respiratory therapy to a patient, the CPAP system comprising: an RPT device configured to provide a flow of air at a therapeutic pressure; a patient interface forming an inflatable chamber pressurizable to said therapy pressure, said patient interface including a seal-forming structure constructed and arranged to form a seal with an area of ​​a patient's face surrounding an entrance to the patient's airway; an air delivery tube configured to convey the flow of air at the therapy pressure from the RPT device to the patient interface; a heat and moisture exchanger (HME) constructed and arranged to retain moisture from an exhaled air stream from the patient, wherein retained moisture from the HME is returned to the air stream for humidification; a controllable heater configured and arranged to heat the HME and / or heat air entering the HME; as well as A controller is configured to regulate heating of the controllable heater to regulate the moisture returned from the HME to the air flow for humidification.

2. The CPAP system according to claim 1, wherein: The controllable heater includes a heating wire provided to the air delivery tube for heating the air flow passing through the air delivery tube.

3. The CPAP system according to claim 2, wherein: The controller is configured to control the power provided to the heating wire.

4. The CPAP system according to claim 1, wherein: The controllable heater is provided to the patient interface.

5. The CPAP system according to claim 1, wherein: The controllable heater is provided to the HME.

6. The CPAP system according to any one of claims 1 to 5, wherein: The HME is disposed within the plenum chamber of the patient interface.

7. The CPAP system according to any one of claims 1 to 5, wherein: The HME is disposed upstream of the plenum chamber of the patient interface.

8. The CPAP system according to claim 7, wherein: The HME is configured to an adapter disposed between the air delivery tube and the patient interface.

9. The CPAP system according to any one of claims 1 to 8, wherein: The seal-forming structure of the patient interface includes a nasal prong.

10. The CPAP system according to any one of claims 1 to 8, wherein: The seal-forming structure of the patient interface includes a nose pad.

Images