Patent Description:
Many individuals suffer from disordered breathing during sleep. Sleep apnea is a common example of such sleep disordered breathing suffered by millions of people throughout the world. One type of sleep apnea is obstructive sleep apnea (OSA), which is a condition in which sleep is repeatedly interrupted by an inability to breathe due to an obstruction of the airway; typically the upper airway or pharyngeal area. Obstruction of the airway is generally believed to be due, at least in part, to a general relaxation of the muscles which stabilize the upper airway segment, thereby allowing the tissues to collapse the airway. Another type of sleep apnea syndrome is a central apnea, which is a cessation of respiration due to the absence of respiratory signals from the brain's respiratory center. An apnea condition, whether obstructive, central, or mixed, which is a combination of obstructive and central, is defined as the complete or near cessation of breathing, for example a <NUM>% or greater reduction in peak respiratory airflow.

Those afflicted with sleep apnea experience sleep fragmentation and complete or nearly complete cessation of ventilation intermittently during sleep with potentially severe degrees of oxyhemoglobin desaturation. These symptoms may be translated clinically into extreme daytime sleepiness, cardiac arrhythmias, pulmonary-artery hypertension, congestive heart failure and/or cognitive dysfunction. Other consequences of sleep apnea include right ventricular dysfunction, carbon dioxide retention during wakefulness, as well as during sleep, and continuous reduced arterial oxygen tension. Sleep apnea sufferers may be at risk for excessive mortality from these factors as well as by an elevated risk for accidents while driving and/or operating potentially dangerous equipment.

Even if a patient does not suffer from a complete or nearly complete obstruction of the airway, it is also known that adverse effects, such as arousals from sleep, can occur where there is only a partial obstruction of the airway. Partial obstruction of the airway typically results in shallow breathing referred to as a hypopnea. A hypopnea is typically defined as a <NUM>% or greater reduction in the peak respiratory airflow. Other types of sleep disordered breathing include, without limitation, upper airway resistance syndrome (UARS) and vibration of the airway, such as vibration of the pharyngeal wall, commonly referred to as snoring.

It is well known to treat sleep disordered breathing by applying a continuous positive air pressure (CPAP) to the patient's airway. This positive pressure effectively "splints" the airway, thereby maintaining an open passage to the lungs. It is also known to provide a positive pressure therapy in which the pressure of gas delivered to the patient varies with the patient's breathing cycle, or varies with the patient's breathing effort, to increase the comfort to the patient. This pressure support technique is referred to as bi-level pressure support, in which the inspiratory positive airway pressure (IPAP) delivered to the patient is higher than the expiratory positive airway pressure (EPAP). It is further known to provide a positive pressure therapy in which the pressure is automatically adjusted based on the detected conditions of the patient, such as whether the patient is experiencing an apnea and/or hypopnea. This pressure support technique is referred to as an auto-titration type of pressure support, because the pressure support device seeks to provide a pressure to the patient that is only as high as necessary to treat the disordered breathing.

Pressure support therapies as just described involve the placement of a patient interface device including a mask component having a soft, flexible sealing cushion on the face of the patient. The mask component may be, without limitation, a nasal mask that covers the patient's nose, a nasal/oral mask that covers the patient's nose and mouth, or a full face mask that covers the patient's face. Such patient interface devices may also employ other patient contacting components, such as forehead supports, cheek pads and chin pads. The patient interface device is typically secured to the patient's head by a headgear component. The patient interface device is connected to a gas delivery tube or conduit and interfaces the pressure support device with the airway of the patient, so that a flow of breathing gas can be delivered from the pressure/flow generating device to the airway of the patient.

One drawback of known patient interface devices is that during therapy, leaks often form between the sealing portion of the cushion and the patient's face. Leaks cause rushes of gas flow against the patient's skin, which can prevent a patient from remaining asleep and also compromise the quality of therapy being delivered to the patient.

<CIT> discloses a patient interface comprising a responsive material for preventing formation of red marks due to contact of the interface with skin of a patient, and/or for reducing leakages of the interface.

<CIT> discloses a cushion element for a patient device having active and passive zones, the active zones activated to expand and/or contract.

<CIT> discloses the adjustment of a patient interface to maintain sealing contact with the patient. A sensor determines the sealing condition, and adjusts the sealing structure to maintain contact.

Accordingly, it is an object of the present invention to provide an improved cushion member and method of manufacturing the same.

In accordance with one aspect of the present invention, a cushion member for a patient interface device is provided according to claim <NUM>.

In accordance with another aspect of the present invention, a method of manufacturing a cushion member for a patient interface device is provided according to claim <NUM>.

These and other objects, features, and characteristics of the present disclosure, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures.

As used herein, the singular form of "a", "an", and "the" include plural references unless the context clearly dictates otherwise. As used herein, the statement that two or more parts or components are "coupled" shall mean that the parts are joined or operate together either directly or indirectly, i.e., through one or more intermediate parts or components, so long as a link occurs. As used herein, "fixedly coupled" or "fixed" means that two components are coupled so as to move as one while maintaining a constant orientation relative to each other.

As employed herein, the statement that two or more parts or components "engage" one another shall mean that the parts exert a force against one another either directly or through one or more intermediate parts or components. As used herein, "directly engage" means that two elements are directly in contact with each other and exert a force against each other. As employed herein, the term "number" shall mean one or an integer greater than one (i.e., a plurality).

As used herein, the phrase "chemical bond" shall mean a bond formed as a result of the curing (i.e., solidifying) of a first material to a second material. In one non-limiting example, the first and second materials are each made of a monomer, a polymer, or a mixture of a monomer and a polymer.

As employed herein, the term "configuration" shall mean a geometric profile not limited by scale or sizing. As employed herein, a component having a geometric profile that increases or decreases in scale or size does not change configuration, whereas a component whose geometric profile changes undergoes a change in configuration.

As employed herein, the term "predetermined" shall mean intentional and preplanned. For example and without limitation, movement of a support portion in an intentional and preplanned manner is movement in a predetermined manner, whereas incidental, unplanned, and/or unintended movement of a support portion is not movement in a predetermined manner.

<FIG> shows an isometric view of a cushion member <NUM>, in accordance with one non-limiting embodiment of the disclosed concept. Cushion member <NUM> may be employed in a suitable patient interface device and be secured to the face of a patient in order to allow pressure support therapy to be delivered to the patient. Cushion member <NUM> includes a body portion <NUM> and a support portion (e.g., without limitation, sealing portion <NUM>) extending from body portion <NUM>. Body portion <NUM> includes a first end <NUM> and a second end <NUM> located opposite first end <NUM>. As shown, body portion <NUM> defines a passage <NUM> therethrough and sealing portion <NUM> extends radially inwardly from second end <NUM> into passage <NUM>. As a result, breathing gas is able to be passed through body portion <NUM> and sealing portion <NUM> to the patient.

Sealing portion <NUM> includes a first portion <NUM> and a number of other portions (e.g., without limitation, second, third, and fourth portions <NUM>, <NUM>, <NUM>) located on first portion <NUM> and facing away from an interior of body portion <NUM>. First portion <NUM> includes a nose bridge region <NUM>, a first cheek region <NUM>, and a second cheek region <NUM> located opposite first cheek region <NUM>. Each of regions <NUM>, <NUM>, <NUM> are positioned so as to engage, respectively, at or about the nose bridge, left cheek, and right cheek regions of a patient. Second portion <NUM> is located on first cheek region <NUM>, third portion <NUM> is located on nose bridge region <NUM>, and fourth portion <NUM> is located on second cheek region <NUM>.

First portion <NUM> is made of a first material and second, third, and fourth portions <NUM>, <NUM>, <NUM> are made of a second material different than first material, and are disposed on the first material. The second material of second, third, and fourth portions <NUM>, <NUM>, <NUM> has a coefficient of thermal expansion and the first material of first portion <NUM> has a coefficient of thermal expansion different than, and in one embodiment less than, the coefficient of thermal expansion of the second material. Additionally, in one embodiment the difference between the coefficients of thermal expansion of the first and second materials is a first number, the average of the coefficients of thermal expansion of the first and second materials is a second number, and the first number divided by the second number is greater than <NUM>.

Sealing portion <NUM> is structured to move from a first configuration (<FIG>) to a second configuration (<FIG>) responsive to a change in environment. In one non-limiting embodiment, the change in environment is a change in temperature. In another non-limiting embodiment, the change in environment is a change in humidity. In one embodiment, the two different materials are both silicone and are each chemically bonded to one another. Changes in temperature or humidity may occur, for example and without limitation, when pressure support therapy is being delivered to a patient, sealing portion <NUM> engages the face of the patient, and leaks occur between the face of the patient and sealing portion <NUM>. That is, gusts of relatively moist and/or hot gas pass over sealing portion <NUM> when there is a leak.

In such a situation, the material of second, third, and fourth portions <NUM>, <NUM>, <NUM> will expand more than the material of first portion <NUM> due to its relatively large coefficient of thermal expansion. As a result, sealing portion <NUM> will change shape, morph, or otherwise deform such that it becomes more outwardly convex, and thus better concentrates sealing forces against the face of the patient. That is, when environmental conditions cause sealing portion <NUM> to change (i.e., due to gas flow or moisture flow between sealing portion <NUM> and the face of the patient), sealing portion <NUM> will change shape and provide an improved seal against the face of the patient. Such arrangement is different from prior art sealing portions (not shown), which are made of one single material, and as such, expand or contract uniformly such that a planar geometric sealing portion will remain a planar geometric sealing portion responsive to a change in environment (i.e., no change in shape). Thus, the dual material sealing portion <NUM>, by virtue of having two separate materials with separate coefficients of thermal expansion, is able to move to a more seal-friendly configuration wherein contact area with the face of the user is decreased, thereby increasing the pressure between sealing portion <NUM> and the face of the user. It follows that the potential for leaks is significantly minimized when cushion member <NUM> is donned, thereby improving the ability of the patient to remain asleep and thus the quality of pressure support therapy being delivered.

<FIG> shows a section view of sealing portion <NUM> in the first configuration and <FIG> shows a section view of sealing portion <NUM> in the second configuration. As shown, the shape of sealing portion <NUM> changes when sealing portion <NUM> moves from the first configuration (<FIG>) to the second configuration (<FIG>), the causation of which is discussed hereinabove. More specifically, the curvature changes such that sealing portion <NUM> is more outwardly convex in the second configuration (<FIG>) than the first configuration (<FIG>). As shown in <FIG>, sealing portion <NUM> has an inner edge portion <NUM> located inboard of second end <NUM> of body portion <NUM>. Cushion member <NUM> has a first center of curvature (not shown in <FIG> because sealing portion <NUM> is relatively flat in the first configuration) when sealing portion <NUM> is in the first configuration and a first radius of curvature <NUM> (partially shown) extending from the first center of curvature to inner edge portion <NUM>. Cushion member has a second center of curvature <NUM> (<FIG>) when sealing portion <NUM> is in the second configuration and a second radius of curvature <NUM> extending from second center of curvature <NUM> to inner edge portion <NUM>. Second center of curvature <NUM> is closer to sealing portion <NUM> than the first center of curvature. Second radius of curvature <NUM> is less than first radius of curvature <NUM>. It will be appreciated that when sealing portion <NUM> moves from the first configuration to the second configuration, sealing portion <NUM> moves in a predetermined manner in order to be more curved. That is, sealing portion <NUM> purposefully changes shape in order to be more outwardly convex, and thus provide an improved seal.

In the exemplary embodiment of <FIG>, second, third, and fourth portions <NUM>,<NUM>,<NUM> substantially overlay first cheek, nose bridge, and second cheek regions, respectively, when cushion member <NUM> is engaged with the face of a patient. These are locations where leaks between sealing portions and the face of the patient commonly occur. However, it will be appreciated that a second material may be located on any location and in any configuration on a first portion being made of a different first material, without departing from the scope of disclosed concept. Additionally, as discussed herein, support portion <NUM> is a sealing portion <NUM> structured to directly engage the face of a user. However, it will be appreciated that the disclosed dual material concept may be employed with, for example and without limitation, another support portion that extends into passage <NUM>, but that is positioned between sealing portion <NUM> and first end <NUM> and is structured to directly support and engage sealing portion <NUM> (e.g., without limitation, a support which underlies a sealing flap which directly engages the face of a patient).

<FIG> shows an isometric view of a cushion member <NUM>, in accordance with the present invention. Cushion member <NUM> has a body portion <NUM> having opposing ends <NUM>, <NUM>, and a support portion (e.g., without limitation, sealing portion <NUM>) extending from second end <NUM> into a passage <NUM> defined by body portion <NUM>. As shown, sealing portion <NUM> has a first portion <NUM> and a number of other portions <NUM>, <NUM>,<NUM>, <NUM> located on first portion <NUM>. For economy of disclosure, only portions <NUM>, <NUM>, <NUM>, <NUM> located on a cheek region of first portion <NUM> will be discussed in detail, although it will be appreciated that sealing portion <NUM> has a number of other portions located on nose bridge region of first portion <NUM> and the corresponding opposing cheek region of first portion <NUM>.

<FIG> shows sealing portion <NUM> in a first configuration and <FIG> shows sealing portion <NUM> in a second configuration. It will be appreciated that sealing portion <NUM> changes shape (i.e., becomes more convex and/or has a reduced radius of curvature) when moving from the first configuration (<FIG>) to the second configuration (<FIG>) responsive to a change in environment (e.g., without limitation, temperature and/or humidity), thereby providing substantially the same improved sealing advantages as sealing portion <NUM> (<FIG>), discussed above. However, as shown in <FIG>, portions <NUM>, <NUM>, <NUM>, <NUM> partially extend into first portion <NUM>, rather than primarily overlaying first portion <NUM>, as is the case with portions <NUM>, <NUM>, <NUM> and portion <NUM>. As a result, sealing portion <NUM> is advantageously able to provide a roughened, multifaceted sealing surface. More specifically, sealing portion <NUM> further has an engaging portion <NUM> structured to engage the face of a user. Engaging portion <NUM> faces away from an interior of body portion <NUM>. When sealing portion <NUM> is in the first configuration (<FIG>), engaging portion <NUM> is generally smooth. When sealing portion <NUM> is in the second configuration (<FIG>), engaging portion <NUM> is roughened such that portions <NUM>, <NUM>, <NUM>, <NUM> extend outwardly from an interior of first portion <NUM>.

It will however be appreciated that a similar suitable alternative sealing portion (not shown and not being part of the present invention) could have second portions inset from a first portion in a first configuration such that in a second configuration the first and second portions would be smooth, and not roughened. Additionally, although support portion <NUM> has been described as a sealing portion <NUM>, it will be appreciated that the disclosed dual material concept may be employed with, for example and without limitation, another support portion that extends into passage <NUM>, but that is positioned between sealing portion <NUM> and first end <NUM> and is structured to directly support and engage sealing portion <NUM> (e.g., without limitation, a support which underlies a sealing flap which directly engages the face of a patient).

<FIG> shows a section view of another support portion (e.g., without limitation, sealing portion <NUM>) in a first configuration and <FIG> shows a section view of sealing portion <NUM> in a second configuration. Sealing portion <NUM> includes a first portion <NUM> made of a first material having a first coefficient of thermal expansion and a number of other portions <NUM>, <NUM>, <NUM> made of materials having different coefficients of thermal expansion than the material of first portion <NUM>. In this manner, sealing portion <NUM> moves between positions responsive to a change in environment (e.g., without limitation, temperature and/or humidity) in the same manner as sealing portions <NUM>, <NUM>, discussed above. However, as shown, portions <NUM>, <NUM>, <NUM> are generally triangular-shaped and extend substantially the entire way through first portion <NUM>. As such, because the relatively thick upper portions (i.e., proximate the engaging surface) of portions <NUM>, <NUM>, <NUM> expand more than the relatively thin lower portions of portions <NUM>, <NUM>, <NUM>, when sealing portion <NUM> is in the second configuration (<FIG>), the engaging surface is relatively smooth. Furthermore, it is also within the scope of the disclosed concept for each of portions <NUM>, <NUM>, <NUM> to be made of a different material, advantageously allowing better control over the resultant shape of sealing portion <NUM> in the second configuration (<FIG>). Accordingly, the size, shape, material, and/or dimensions of second portions <NUM>, <NUM>, <NUM> may be varied without departing from the scope of the disclosed concept.

Cushion members <NUM>, <NUM> and a cushion including sealing portion <NUM> may be made by, for example and without limitation, a suitable method of three-dimensionally printing two different materials on one another, known as 4D printing. As such, a method of manufacturing a cushion member <NUM>, <NUM> includes the steps of providing body portion <NUM>, <NUM>, providing first portion <NUM>, <NUM>, <NUM>, and providing second portion <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The providing first portion <NUM>, <NUM>, <NUM> step may further include printing first portion <NUM>,<NUM>,<NUM> with a three-dimensional printer, and the providing second portion <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> step may further include printing second portion <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> with the three-dimensional printer. The providing second portion <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> step may further include overmolding second portion <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> on first portion <NUM>, <NUM>, <NUM>. Accordingly, it will be appreciated that first portion <NUM>, <NUM>, <NUM> and second portion <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> can either together, or in any combination, be provided by a suitable three-dimensional printing process or by an overmolding process.

Accordingly, it will be appreciated that the disclosed concept provides for an improved (e.g., without limitation, better able to seal against a face of a patient and thereby minimize the occurrence of leaks during therapy) cushion member <NUM>, <NUM> and method of manufacturing the same, in which a support portion <NUM>, <NUM>, <NUM> changes shape responsive to a change in environment (e.g., without limitation, temperature and/or humidity).

Claim 1:
A cushion member (<NUM>) for a patient interface device, the cushion member comprising:
a body portion (<NUM>) comprising a first end (<NUM>) and a second end (<NUM>) disposed opposite the first end, the body portion defining a passage (<NUM>) therethrough; and
a support portion (<NUM>) extending from the second end into the passage, wherein the support portion has an engaging portion (<NUM>) structured to engage a face of a user, wherein the engaging portion faces away from an interior of the body portion, the support portion comprising a first portion (<NUM>) and a second portion (<NUM>,<NUM>,<NUM>,<NUM>) partially extending into the first portion, wherein the support portion is movable from a first configuration to a second configuration responsive to a change in environment, thereby changing shape,
wherein the first portion is made of a first material having a first coefficient of thermal expansion, and wherein the second portion is made of a second material having a second coefficient of thermal expansion different than the first coefficient of thermal expansion, and
wherein, when the support portion is in the first configuration, the engaging portion is generally smooth, and when the support portion is in the second configuration, the engaging portion is roughened.