Patent Grant
11883598
The present invention relates to respiratory therapies, including but not limited to, Continuous Positive Airway Pressure (CPAP), bi-level and ventilation therapies. The present invention also relates to a mask and flow generator system that delivers a flow of pressurized breathable gas, e.g. air, to a patient for treatment of various breathing disorders. Tue present invention further relates to a system in which the flow generator is incorporated with the mask or a headgear that supports the mask.
Obstructive Sleep Apnea (OSA) is a sleep breathing disorder (SBD). For those who have OSA when they sleep the soft tissue in their throat and airway relax and collapse thus blocking the airway and preventing airflow to the lungs. This cessation of breathing, known as an apnea, can last for up to one minute before the blood oxygen levels reach a critical point where the patient has an arousal and their airway reopens. Most OSA suffers do not remember these arousals however each arousal places extra strain on a patient's heart and destroys the quality of their sleep.
OSA is as prevalent as diabetes or asthma but is an extremely undiagnosed condition. Studies have shown it can lead to significant health problems if left untreated.
The treatment for OSA may include CPAP. CPAP involves the patient wearing a nasal or facemask that delivers positive pressure into the patients airway. This acts as a pneumatic splint and holds the patients airway open to prevent apneas.
2.1 Mechanical Ventilation
A mechanical ventilator is a machine that generates a controlled flow of gas into a patient's airways and is configured to assist patients who are unable to maintain self-sufficient respiration.
Patients generally require mechanical ventilation for three main reasons. These include
A mechanical ventilator essentially performs the role of the medulla in that it initiates respiration and the diaphragm by expanding and contracting the lungs. A mechanical ventilator may also assist the patient in respiration once the patient begins respirating.
Mechanical ventilators can be sub-categorised into invasive and non-invasive ventilators. Invasive ventilators actually enter the body, whereas non-invasive ventilators perform the function external to the body.
These two sub-categories can be further sub divided into positive and negative pressure devices, referring to the type of pressure that is used to expand the lungs.
In negative pressure devices, a negative gauge pressure is created external to the chest, thus drawing the chest outwards and dilating the lungs, for example as with an iron lung.
In positive pressure devices, a positive gauge pressure is created inside the lungs thus drawing air into the lungs.
Clinical studies have illustrated the benefits that Non-Invasive Positive Pressure Ventilation (NIPPV) has over the other ventilation devices. This includes significantly reducing the number of complications such as infection, no loss of the airway defense mechanism, and reduced need for patient sedation.
NIPPV is a suitable treatment for a wide range of diseases and conditions. These include:
One aspect of the invention relates to enhancing the treatment delivery by a device that incorporates all, or most, of the components of a NIPPV system into a single wearable device. For example, the mask and flow generator may be integrated into a mask system worn by the patient. The flow generator may be incorporated into the mask or a headgear configured to support the mask. This aspect provides several advantages over current NIPPV systems.
Another aspect of the invention relates to a patient interface that incorporates a flow generator and provides effective treatment while maintaining or improving patient comfort, including the reduction of pressure points on the patient's face and the reduction of vibration and noise transmittance to the patient, without obstructing the patient's vision.
According to one sample embodiment of the present invention, a system for delivering a pressurized flow of breathable gas to a patient comprises a patient interface configured to contact a wearer's head, the patient interface comprising a frame, a cushion supported by the frame and configured to sealingly connect the patient interface to the patient's face and form a chamber between the frame and the wearer's face, and ˜n inlet port in the frame to receive the pressurized flow of breathable gas. A flow generator is configured to generate the pressurized flow and is capable of creating a pressure of about 2-40 cm H2O in the chamber. A flow generator housing is provided to house the flow generator. The flow generator housing is mounted on the patient interface and configured to reduce the transmission of vibration and/or noise generated by the flow generator to the patient interface.
3.1 Reduction in Mask Leakage
One advantage is a reduction in mask leakages. Leaks between the patient's face and the mask are a significant issue for NIPPV and may be caused by the force of the air tube pulling on the patient interface, e.g., mask. So by removing the tube this cause of leaks is eliminated.
3.2 Improved Treatment Accuracy
Another advantage is the improvement of treatment accuracy. The impedance and length of the tube imparts a lag in the response and rise time in the pressurised air from the flow generator to the mask. This can reduce treatment efficacy, but by removing the tube this problem is eliminated.
3.3 Increased Useability
Still another advantage is that the system is easier to use and also increases mobility of the patient while they are wearing the device, making it suitable for many applications.
3.4 Reduction in Functional Dead Space
An even further advantage of the present invention associated with the removal of the air tubing is a reduction in the functional dead space of the mask. Functional dead space is defined as the volume of exhaled air that is trapped within the system and that the patient subsequently re-breathes. It is desirable that functional dead space is kept within a safe range, or in the most extreme cases this could lead to the eventual patient suffocation. Current techniques to reduce functional dead space involve minimizing internal volume of the mask to minimize the amount of CO2 that is re-breathed and maximising the vent size and thus air flow through the mask to flush out the trapped CO2. Part of the CO2 that is re-breathed by the patient comes from the exhaled air that is breathed back into the tube. By removing the tube this reduces the physical volume that is available to trap CO2 and hence reduces functional dead space. This has implications for mask design. The first implication is that the internal volume of the mask can be made larger to increase the range of fit for each mask. The second implication is that this could lead to reduced flow requirements. If less CO2 is trapped in the mask, then the required flow rate to remove this CO2 is less. Reducing the flow rate will lead to a reduction in noise created as air rushes through the vents, reduce the power requirements of the pump, and increase patient comfort.
Sample embodiments of the invention will be described below with reference to the attached drawings, in which:
Referring to
A power supply connector 10 may be provided to the user interface 8 to provide power to the user interface 8. The power supply connector 10 may also be configured to charge a rechargeable battery of the user interface 8.
The patient interface 2 may also include a headgear 12 configured to secure the mask 4 to the patient's face so that the mask 4 forms a substantially leak proof seal with the patient's face.
An electrical connector 14 may be provided between the user interface 8 and the patient interface 2. Electrical signals may be provided between the user interface 8 and the patient interface 2 by the electrical connector 14. As shown in
The user interface 8 may include a programmable logic controller, or microcontroller, configured to control the operation of the flow generator 6. User controls, such as buttons, dials, etc., may be provided to allow the user to operate the user interface 8. The user interface 8 may include, for example, a display, such as a graphic LCD, a keypad, a motor control, a user interface control, a power supply, an indicator or alarm, such as an audible buzzer and/or LED's.
4.1 First System Configuration Sample Embodiment
Referring to
4.2 Second System Configuration Sample Embodiment
As shown in
4.3 Third System Configuration Sample Embodiment
4.4 Fourth System Configuration Sample Embodiment
Referring to
4.5 Fifth System Configuration Sample Embodiment
According to another sample embodiment shown in
4.6 Sixth System Configuration Sample Embodiment
As shown in
4.7 Seventh System Configuration Sample Embodiment
Referring to
4.8 System Configuration Components
According to the sample embodiments described above, the patient interface 2 may delivers the pressurised air flow into the patient's airways and may include some or all of the following components:
The second component, i.e., the user interface 8 may be configured to control the operation of the flow generator and may include some or all of the following components:
Referring to
The mask shell 4a may include an extension 4c. A forehead support may be attached to the mask extension 4c to stabilize the mask 4 against the wearer's face once a comfortable, substantially leak proof fit is obtained. The mask shell 4a may also include headgear connectors 4e, including a headgear connector on the extension 4c, to receive straps of the headgear 12 to secure the system to the user's head.
As shown in
Referring to
A motor and volute housing second part, or cover, 6f is configured to cover the motor housing first part 6a (part of an upper portion of a housing for the flow generator 6) and the volute housing first part 6b (part of a lower portion of the housing for the flow generator 6), as shown in
Although the motor housing first part 6a and the volute housing first part 6b and the cover 6f have been described as connected by fasteners, it should be appreciated that they may be connected by other mechanisms, such as adhesive or by complementary mating and locking (e.g. snapping) surfaces.
5.1 User Interface
5.1.1 Design Consideration: Useability
The system of the present invention is configured to be simple (e.g., intuitive) to use and communicate clearly with the user, both for experienced and inexperienced users.
5.1.2 Design Approach: Usability
To provide a “user friendly system,” a significant amount of information may be required to be communicated to the user. This functional requirement may influence the selection of mechanisms to communicate with the user. The system of the present invention may include at least one of the following forms of communication:
To achieve clear communication, the communication devices should located in logical and intuitive places. For example, according to one sample embodiment, all of the visual communication devices (e.g., LED's, LCD, etc.) are visible at all times while the system is in use.
5.1.3 Design Consideration: Sanitization and Housing Durability
The user interface 8 may be worn on the patient's body. Because the user interface may be exposed to bodily fluids it should be void of cracks and groves that may harbor infectious particles.
5.1.4 Design Approach: Sanitization and Housing Durability
The user interface may be designed to be void of cracks and grooves that may harbor infectious particles. This can be achieved using such manufacturing techniques, such as overmolding. The user interface housing material should be resistant to oils, dusts, and grease and the ingress of water. The user interface housing should also be durable, with high levels of cut, fade and abrasion resistance. All external connections of the user interface, such as power connections and connections to the patient interface, should be configured to withstand being cleaned.
5.1.5 Design Consideration: Safety
The system of the invention may be configured to communicate with the user if an alarm has been triggered. The system of the invention may also be configured to prevent accidental user input, and to prevent accidental power supply disconnection.
5.1.6 Design Approach: Safety
In one sample embodiment, buttons or other forms of user input of the user interface may be located at a position that they cannot be activated accidentally. In addition, software control could be implemented to ensure that a specific set of buttons must be pushed in series to confirm a setting change.
According to a sample embodiment, the user interface may indicate when an alarm is triggered using at least one of the following techniques:
To prevent the power supply from accidental disconnection, the power supply connector may include a locking mechanism.
5.2 Mask and Flow Generator Incorporation
As discussed above, the patient interface 2 may include at least one of the mask 4, the headgear 12, the flow generator 6, and sensors (e.g., pressure, temperature, flow and/or volume). In the sample embodiments in which the flow generator is incorporated into the mask, the flow generator housing is configured to mount the flow generator on the mask, secure the connection of the flow generator to the power supply so that it cannot be accidentally disconnected, protect the user from the flow generator inlet and from objects that may enter the air path, and mount any sensor(s), or other electrical devices, to the mask.
Incorporating the flow generator 6 into the mask 4, as disclosed in some of the sample embodiments discussed above, present several design considerations including, but not limited to:
The additional weight of a motor and an impeller of the flow generator on the front of the mask may lead to patient discomfort by increasing the forces that are applied to the patient's face while wearing the mask.
5.2.2 Design Approach: Weight
One or some or all of the following techniques may be used to minimize the weight of the patient interface:
A first approach may be to minimize the mask and motor housing thickness to minimize mask weight. For example, according to one sample embodiment, the thickness of the motor housing first part 6a may be 0.5-2.5 mm, for example 1.0-2.0 mm, or for example 1.5 mm. The thickness of the volute housing first part 6b may also be 0.5-2.5 mm, for example 1.0-2.0 mm, or for example 1.5 mm. The motor and volute housing second part, or cover, 6f may also have a thickness of 0.5-2.5 mm, for example 1.0-2.0 mm, or for example 1.5 mm.
5.2.3 Design Consideration: Mask Stability
The additional weight of a motor and an impeller of the flow generator on the front of the mask may also create instability of the mask on the face of the patient, which may cause patient discomfort and reduce the effectiveness of the therapy if the instability prevents substantially leak proof contact between the cushion and the patient's face.
5.2.4 Design Approach: Mask Stability
One approach to providing stability to a mask having an incorporated flow generator is shown in
In determining the location of the flow generator 6 on the mask 4, three factors may be considered. The first factor is that as the distance between the patient's face and the center of gravity of the motor and impeller increases, the moment between the flow generator and the mask increases, thus creating greater mask instability. The second factor is the location of the motor and the impeller location should assist in reducing the number of components of the system, such as connecting tubes or conduits, and should not lead to decreased patient comfort, e.g., such as obstructing the patient's vision. The third factor is the weight of the motor and impeller should be evenly distributed across the surface area of the mask cushion that contacts the patient's face. Any localized pressure points would greatly enhance the possibility of patients developing pressure sores in these areas, and the mask should be stabilized so as to reduce, or eliminate, such localized pressure points.
According to sample embodiments of the invention, the location of the flow generator on the mask was selected to be on the front of the mask, located as to be out of the field of vision of the patient to minimize the obtrusiveness of the system. The flow generator was also rotated and positioned such that the centre of gravity of the flow generator is located as close to the patient's face as possible to minimize instability. The flow generator was also located in a position to evenly distribute the additional weight across the entire lower half of the patient's face.
An analysis of the most common facial areas to suffer from pressure sores highlights the areas of the face where bones and other hard tissue are located close to the surface and covered by only small thicknesses of soft facial tissue. This includes areas such as across the bridge of the nose, on the forehead and on the cheekbones. By locating the motor and the impeller in this position, the additional pressure is isolated to areas of the face that can withstand an increase in pressure. Referring to
5.2.5 Design Consideration: Noise and Vibration
As the flow generator operates it produces three outputs. The first output is a pressurised airflow. The second and third outputs are side effects of the production of the pressurised airflow, noise and vibration. These side effects may cause patient discomfort, and eventual patient harm if worn for extended periods.
The motor 6d and impeller 6e create noise as they generate the pressurised airflow. This is a consideration because of the close proximity of the motor 6d and the impeller 6e to the patient's face. The close proximity of the motor 6d and the impeller 6e may cause patient discomfort and inhibit patient recovery if it interferes with the patient's rest or sleep.
For a centrifugal fan system, as may be used in the sample embodiments of the system of the invention, there are two primary sources of noise:
The sound power produced by a centrifugal fan can be estimated by using the following formula:
LW=KW+10 log 10 Q+20 log 10 P+BPI+CN,
where:
The first component of the noise emitted by the flow generator is referred to as tone or harmonic noise and is due to the rotation of the impeller blades past a fixed position. The specific frequency of this noise is known as the blade pass frequency (BPF). The BPF is equal to the number of blades N times the Revolutions Per Minute (RPM) of the rotor, as defined by the formula:
BPF=N·RPM
The tone or harmonic noise is a problem for centrifugal fans and influences their design. The frequency output of a single and a three blade impeller are pictured in
5.2.5.2 Broadband Noise
The second component of the noise emitted by a centrifugal fan system is broadband noise. Broadband noise is the random non-periodic signal that is caused by the turbulent flow of air over the blades. An example of a broadband noise that is typical of a rotating impeller is shown in
5.2.5.3 Total Noise
The sum of the blade broadband and tone noise is shown in
5.2.6. Design Approach: Noise and Vibration
The majority of noise sources can be attributed to vibrating surfaces. Therefore, vibration control is an aspect of noise reduction.
5.2.6.1 Sound Control
To sound proof the mask and the motor housing there are two different techniques that may be used, alone or in combination: noise reduction and noise absorption. A third technique, including the use of a soft joint, may also be used.
5.2.6.2 Noise Absorption
Noise absorption operates by transforming the sound wave into another form of energy and acts to suppress the sound. As shown in
15 5.2.6.3 Noise Reduction
The second technique that may be used is noise reduction. Noise reduction includes placing a physical barrier to prevent the transmission of sound. In this situation, the physical barrier is the actual motor housing (i.e., the motor housing first part 6a, the volute housing first part 6b and the cover 6f) and this reflects the sound, for example back into the noise absorbing material 6m. The amount of noise reduction that is possible can be directly correlated to the mass of the physical barrier, hence there will be a trade off between noise reduction and weight issues as discussed previously. The depiction in
5.2.6.4 Soft Flexible Joint
Another approach is shown in
5.2.6.5 Vibration Control
Vibration control can be achieved by using three different techniques, isolation, damping and avoiding resonance.
5.2.6.6 Vibration Isolation
A proportion of the noise produced by a centrifugal fan system, which may be used as a flow generator in system according to the invention, can be attributed to vibration. Noise is produced when vibration from one source is transferred to another system that is a better noise radiator than the previous source. In a centrifugal fan system this occurs when the vibration of the motor and impeller is transferred to the flow generator housing and mask. This transfer causes the system to act almost as a speaker. Vibration isolation is thus useful in minimizing noise output.
It is possible to minimize the transmission of vibration from one structure to the next structure by placing an elastic material between the two structures. The elastic materials are often referred to as vibration isolators and have material properties that make them suitable for such a purpose.
According to Tandon N., Noise-reducing Designs of Machines and Structures, Siidhanii, Vol. 25, Part 3, June 2000, pp 331-339, vibration isolation can be understood from the analysis of an ideal, linear, single degree of freedom system in which the isolator is represented by the parallel combination of a massless spring and a damper, as shown in
The transmissibility of a substance is defined as the ratio of the amplitude of the force transmitted to the supporting structure to that of the exciting force, and can be expressed by the formula:
T={[1+(2ζr)2]/[1−r2)2+(2ζr2)2]}1/2,
where T is the transmissibility, ζ is the damping ratio and r is the ratio of the excitation frequency to the natural frequency of the spring mass system. When T is less then one then the system is in isolation. Hence the system is in isolation when r>20.5. This means that for a substance to be an effective isolator its stiffness must be such that the mounted resonance frequency is less then 0.7 times the minimum forcing frequency. If r is near 1 then this could lead to the vibration being amplified rather then attenuated.
While this model provides an insight into vibration isolation it is not a completely accurate description of vibration in real world circumstances. Vibrating bodies rarely vibrate only vertically and real springs are not massless. However, the model shown in
Many vibration isolators are commercially available and are generally metallic (coil springs or some other form of flexural configuration) or elastomeric resilient elements. Elastomeric elements are suitable for using is situations where vibrations are caused by shear, torsion, compression modes or any combination of these. The loss coefficient versus Young's modulus for various elastomers and other materials is shown
5.2.6.7 Vibration Dampening
Three general properties may be used to describe the noise characteristics of a structure. These properties include mass, stiffness and damping. Mass and stiffness are associated with the storage of kinetic and shear energy, respectively, whereas damping is associated with the dissipation of energy. Damping is the process by which sonic vibrations are converted to heat over time and distance. Damping results in the decay of unforced vibrations and leads to the reduction in the amplitude of resonance frequency for an object subjected to steady excitations. The damping capacity, ψ, of an element is defined as the ratio of energy dissipated per cycle to the energy present in the system. The term used to specify material damping is the loss factor, η, which may be determined according to the following formula:
η=(ψ/2π)=2ζ.
Several methods may be used to dampen sound. A first method is to use a high-density soft material, such as lead. The softness and high density combine to dampen the noise rather then transmit it.
Another method is to place material of different densities in the path of the sound waves. The sound waves are forced to travel through the different densities thus reflecting and dampening the sound. This is why open cell foam is such an effective sound dampener
15 5.2.6.8 A voiding Resonance
Resonance is defined as the tendency for a system to oscillate with high amplitude when excited by energy at a certain frequency. Therefore, when designing a structure to minimize the transmission of sound, it is desired that the resonant or natural frequency does not correspond to the frequencies of the excitation forces. This may be a consideration when selecting the final production material and the effect should also be considered when testing different prototype configurations. For an object of a simple geometry, its resonant frequency F may be determined according to the following formula:
F=0.5π(stifness0.5/mass0.5).
In order for NIPPV therapy to be effective, the patient may e required to use the system for several hours, during which time the patient may be sleeping. In order to allow the patient to use the system for such a time, user comfort should be a consideration. One of the issues for patients wearing a respiratory mask is that it does not inhibit their primary senses, for example sight. It is therefore desirable that the location of the flow generator on the front of the mask does not impinge the patient's field of vision.
Another issue of patient comfort is the weight of the flow generator and mask when these components are incorporated. This consideration was previously discussed with respect to the mask and flow generator weight and the stability of the mask and flow generator when worn by the patient.
5.2.8 Design Approach: Patient Comfort
One sample method for preventing the pump from impinging on the patient's field of vision is to locate the pump in such a way that it is out of the patients field of vision. According to one sample embodiment shown in
5 6 Flow Generator
6.1 Pump
The flow generator 6 is configured to generate the pressurized flow of respiratory gas. The flow generator 6 may include a motor 6d, an impeller 6e and a volute 6c. The motor 6d, the impeller 6e and the volute 6c may be referred to as a pump.
6.1.1 Motor
The motor 6d may be a brushless DC (BLDC) motor. A BLDC motor has advantages over DC motors including brushes. One advantage is that the BLDC motor does not require brushes. The BLDC motor can operate at higher maximum speeds and is far less likely to create sparks. This advantage assists in the safe delivery of oxygen. As oxygen is extremely flammable, the creation of sparks is a safety issue.
BLDC motors also require less maintenance because there is reduced frictional contact. BLDC motors also typically operate at cooler temperatures, increasing the lifespan of the internal components. BLDC motors are also more efficient than DC motors with brushes, with a typical efficiency of 85-90% compared to brushed motors that at best deliver an efficiency of 80%. BLDC motors also provide more precise speed control. This is a desirable advantage for the system of the present invention because it enables the system to deliver accurate and effective treatment.
6.1.2 Impeller and Volute
The impeller 6e is driven by the motor 6d to generate the pressurized flow of respiratory gases. The impeller 6e may be a rotating disk that has a set of veins that, when rotated, produce centrifugal force within the volute 6c. The volute 6c is the stationary housing that encompasses the impeller 6e and collects, discharges and recirculates the air entering the pump. As shown in
6.2 Sensors
In the sample embodiments of the system of the present invention, sensors may be incorporated into the patient interface 2 to measure at least one of the following:
To measure pressure, a pressure sensor(s) requires access to space where the pressure is to be measured. In the sample embodiments of the system of the present invention, this is in the air path or inside the mask.
In one sample embodiment, an obtrusive flow sensor may be used to measure flow. An obtrusive-flow sensor operates by placing a small obstruction in the flow and measuring the pressure drop across the obstruction. The obstruction is commonly known as an orifice plate 28 (
Q=k√(P1−P2)
where:
Volume can then be determined by integrating flow with respect to time.
An example of a pressure sensor that could be used in one sample embodiment is the MPXV 5004G pressure sensor manufactured by Freescale Semiconductors. An advantage of the MPXV5004G series is that it is designed for a wide range of applications, including those employing a microcontroller with analog to digital outputs. The pressure range of this sensor also matches required pneumatic performance for most NIPPY therapies with a pressure range of 0 to 40 cm H2O.
The user interface 8 may be configured to receive signals from pressure sensors at the test ports on the sides of the orifice plate 28. The user interface 8 may be configured to calculate the volume and flow of the pressurized gas. The user interface 8 may also control the operation of the motor 6d to deliver the pressurized gas flow at a desired pressure and volume. For example, the NIPPV therapy may be a Continuous Positive Airway Pressure (CPAP) therapy, a Variable Positive Airway Pressure (VP AP) therapy, or a Bi-level Positive Pressure Airway Pressure (BiP AP) therapy.
7.1 First Patient Interface Sample Embodiment
Referring to
Noise absorbing material 6m may be provided in the pump housing, both in the motor housing first part 6a and the impeller housing first part 6b incorporated in the mask shell 4a and in the cover 6f. The noise absorbing material 6m may be, for example, a 5 mm layer of polyethylene foam. The foam is configured to support the pump, prevent vibration transmission 20 and dampen noise emitted from the pump.
7.2 Second Patient Interface Sample Embodiment
Referring to
Referring to
One part of the pump housing 30 houses a pressure sensor 40, as shown in
The techniques of noise dampening and vibration isolation used in the first sample embodiment of the patient interface may also be used in the second sample embodiment of the patient interface. In the second sample embodiment, however, the space between the interior wall of the pump housing 30 and the motor and impeller may be increased to allow the insertion of noise absorption and reflection foam. This foam not only provides the sound damping qualities used in the first sample embodiment of the patient interface, but it also provides additional attenuation and reflection due to the high density layer laminated onto the outer wall.
Referring to
Another technique used to minimize the transmission of vibration from the pump housing to the mask is the design of the support arms 30c that attach the pump housing to the mask. In the second sample embodiment, two support arms 30c are used to attach the pump housing 30 to the mask. However, it should be appreciated that more or less supporting arms 20c between the housing and the mask may be provided. It should also be appreciated that the pump housing 30 may be formed as a fully integrated structure, as shown in
The inlet 30f and the outlet 30e of the pump housing 30 may require safety features to prevent harm to the patient. As shown in
Another feature of the second patient interface sample embodiment is the inclusion of a housing to hold a pressure sensor. This is located on the flow generator housing.
As is shown in
One difference between the patient interface of the second sample embodiment and the patient interface of the first sample embodiment is that patient interface of the second sample embodiment may be, with minor modifications, mounted on any mask, whereas the patient interface of the first sample embodiment requires a customized mask.
It should be appreciated that the design considerations discussed above are not exhaustive. Other design considerations may also be accounted for by the sample embodiments described above. For example, the visual appearance of the mask and flow generator system, humidification of the pressurized flow, the safety of the oxygen delivery, sterilization of the system, fail safety procedures and precautions, and ergonomic issues may all be considered in the design of the system of the present invention.
While the invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. Further, each independent feature or component of any given assembly may constitute an additional embodiment. Furthermore, each individual component of any given assembly, one or more portions of an individual component of any given assembly, and various combinations of components from one or more embodiments may include one or more ornamental design features. In addition, while the invention has particular application to patients who suffer from OSA, it is to be appreciated that patients who suffer from other illnesses (e.g., congestive heart failure, diabetes˜morbid obesity, stroke, barriatric surgery, etc.) can derive benefit from the above teachings. Moreover, the above teachings have applicability with patients and non-patients alike in non-medical applications.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006904900 | Sep 2006 | AU | national |
| 2006905967 | Oct 2006 | AU | national |
This application is a continuation of U.S. application Ser. No. 15/952,988, filed Apr. 13, 2018, which is a continuation of U.S. application Ser. No. 12/438,899, filed Feb. 25, 2009, which is the U.S. national phase of International Application No. PCT/AUI2007/001325, filed Sep. 6, 2007, which designated the U.S. and claims priority to Australian Provisional Applications 2006904900 and 2006905967, filed Sep. 7, 2006 and Oct. 27, 2006, respectively, the entire contents of which are incorporated herein by reference. WO 2005/028009 is also incorporated herein by reference in its entirety.
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| Child | 16998434 | US | |
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| Child | 15952988 | US |
