Sealing cushion having corrugated sealing flap

A cushion (26) for a patient interface device includes a support wall portion having a first edge and an opposite second edge, and a sealing flap (40) extending in a cantilevered fashion inwardly from the second edge and toward a longitudinal axis of the cushion such that when the patient interface device is donned a portion of the face of the user will engage the top outer surface of the sealing flap to form a seal. The sealing flap includes a corrugated portion (56), wherein the corrugated portion commences at a distal edge of the sealing flap and extends toward a proximal edge of the sealing flap along at least a portion of a width of the sealing flap. The corrugated portion includes a series of alternating furrows and ridges.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to patient interface devices structured to deliver a flow of breathing gas to a user, and, in particular, to a sealing cushion for a patient interface device that has a corrugated sealing flap.

2. Description of the Related Art

There are numerous situations where it is necessary or desirable to deliver a flow of breathing gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube into the patient's esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation. It is also known to deliver positive airway pressure (PAP) therapy to treat certain medical disorders, the most notable of which is OSA. Known PAP therapies include continuous positive airway pressure (CPAP), wherein a constant positive pressure is provided to the airway of the patient in order to splint open the patient's airway, and variable airway pressure, wherein the pressure provided to the airway of the patient is varied with the patient's respiratory cycle. Such therapies are typically provided to the patient at night while the patient is sleeping.

Non-invasive ventilation and 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 a 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 sealing cushion typically has a support portion coupled to a sealing flap portion, which may integrated together as a single part or that may be separate components that when combined together in the final assembly provide the sealing and support functions. The patient interface device is connected to a gas delivery tube or conduit and interfaces the ventilator or 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. It is known to maintain such devices on the face of a wearer by a headgear having one or more straps adapted to fit over/around the patient's head.

Patient interface devices used in non-invasive ventilation and pressure support therapies should be comfortable and maintain a robust seal, while at the same time optimizing comfort by avoiding the creation of excessive pressure and/or red marks on the user's face. The sealing flap portion should also conform to the face without excessive bunching and encroaching on the patient's eyes, cheeks, and nostrils. As used herein, the term “bunching” shall refer to an area where, when the sealing cushion is donned by the user, extra sealing flap length collects and folds/curls over itself, resulting in bunches or folds of sealing flap. Bunching can cause patient annoyance, obstruct the patient's view, partially obstruct the patient's air path, and/or create potential leak paths, any or all of which may ultimately decrease the patient's therapy compliance.

Unfortunately, many current patient interface devices used in non-invasive ventilation and pressure support therapies have sealing problems, create pressure on the face, and/or cause red marks and/or sores. One location where such problems, especially pressure points, frequently occur is on and around the bridge of the nose where the sealing flap seals against the patient.

These problems are primarily due to the geometry utilized in current sealing cushions. In particular, traditionally, patient interface devices have sealing flaps which either (i) are all convex without any reversals along the opening circumference (i.e., distal end) of the sealing flap, or (ii) have a single change in the flap opening geometry from convex to concave. This creates a finite arc length of the sealing flap distal end defining the sealing flap opening that must conform to an infinite number of potential patient facial (e.g., nose bridge) geometries. The traditional designs of one or no reversals in the sealing flap opening circumference must therefore rely on the flexibility and elongation of the material used to stretch and conform to all patient faces. However, because the length of the sealing flap distal end is finite, when compressed against the patient's face, it tends to create excess pressure and resultant red marks across and on the patient's face (e.g., at the bridge of the patient's nose). This is due to the sealing flap compressing against the face and applying compressive, tensile, and shear forces all at the same time and in multiple directions. For example, using the nose bridge as one particular illustration, as the sealing cushion is compressed and tightened against the face, the finite opening circumference of the sealing flap (typically made of an elastomeric material such as TPE, silicone, rubber, etc.) must flex and stretch into the nose bridge (−z direction), up or down the nose bridge (+y or −y direction) and across the nose bridge (+ and −x directions) as it conforms to the patient's nose to create a seal.

In traditional designs, attempts are often made to make a sealing cushion having a sealing flap that will fit all patient nose bridges and depths. However, if the length of the flap is not a perfect match for a particular user, negative fit and comfort situations will likely occur. Specifically, on some patients, the sealing flap will be too short and will not fully seat against the nose. As a result, a robust seal may not be formed and/or the sealing flap will stretch too tightly across the nose bridge and cause excessive pressure and red marks. On other patients, the same sealing flap will be too long and will bunch at the patient's eyes and encroach on their vision and/or create leak paths (because the flap's excess length mistakenly and easily locates the top arc of the sealing flap too high on the nose towards the eyes). Alternatively, because of the flap's excess length, it is more likely to mistakenly and easily locate the top arc of the sealing flap too high on the nose towards the eyes, when donned by the user. At such an incorrect location (+ or −y direction), the sealing flap will often too tightly stretch across the nose bridge and therefore causes excessive pressure and red marks.

To remedy these issues, traditional designs have either increased the sealing flap height and depth or decreased the sealing flap height and depth. The problem with these approaches is that each creates additional problems for patients with the opposing facial geometry.

Thus, in short, for traditional sealing flaps, if the circumference of the flap opening is too short and is located at an insufficient height from the interface, it will need to stretch and flex more than desired, or even possible because of material properties, in the x, y, and z directions, especially at the nose bridge areas, in order to create a seal. This will cause excess force and shear against and in line with the nose and skin, which causes discomfort, pressure, and/or red marks. This may also cause leak issues on facial geometries with deep nose features because the flap is too short to form a robust sealing surface area against the face. If the circumference of the flap opening is too long and is located at an excessive height from the interface, there may be seal issues and bunching of the sealing flap. This may cause patient annoyance and discomfort as well as creating potential leak paths. The only way in the current art to alleviate the problem of pressure and red marks on the nose bridge (or other facial areas) is to have multiple sizes (sizes being different circumference openings and sealing flap heights) of each design available to accommodate different facial geometries.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a cushion for a patient interface device that overcomes the shortcomings of conventional cushions. This object is achieved according to the present invention by providing cushion that includes a corrugated sealing flap.

In one embodiment, a cushion for a patient interface device is provided that includes a support wall portion having a first edge and a second edge located opposite the first edge, and a sealing flap extending in a cantilevered fashion inwardly from the second edge and toward a longitudinal axis of the cushion such that when the patient interface device is donned by a user a portion of the face of the user will engage a top outer surface of the sealing flap to form a seal therewith. The sealing flap includes a corrugated portion, wherein the corrugated portion commences at a distal edge of the sealing flap which defines an opening in the sealing flap and extends toward a proximal edge of the sealing flap along at least a portion of a width of the sealing flap including the top outer surface. The corrugated portion includes a series of alternating furrows and ridges, wherein the number of the furrows is at least two or the number of the ridges is at least two.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

As described in detail herein, the invention provides a sealing cushion that utilizes corrugations or waves in the opening circumference of the sealing flap in order to reduce pressure points (e.g., at the nose bridge or other locations) and/or red marks without the need of multiple designs (a single design would conform to multiple patient facial geometry). As detailed herein, the sealing flap is structured to flex, stretch and conform to the face without creating additional compressive and shear force to the areas where the corrugations or waves are implemented.

A system2adapted to provide a regimen of respiratory therapy to a patient according to one exemplary embodiment of the invention is generally shown inFIG. 1. System2includes a pressure generating device4, a delivery conduit6, and a patient interface device8including an elbow conduit10. Pressure generating device4is structured to generate a flow of breathing gas and may include, without limitation, ventilators, constant pressure support devices (such as a continuous positive airway pressure device, or CPAP device), variable pressure devices (e.g., BiPAP®, Bi-Flex®, or C-Flex™ devices manufactured and distributed by Philips Respironics of Murrysville, Pa.), and auto-titration pressure support devices. Delivery conduit6is structured to communicate the flow of breathing gas from pressure generating device4to patient interface device8.

In the illustrated embodiment, patient interface device8comprises a nasal mask structured to cover the nose of the patient. However, other types of patient interface devices8, such as, without limitation, a nasal/oral mask that covers the patient's nose and mouth, or a full face mask that covers the patient's face, which facilitates the delivery of the flow of breathing gas to, and the removal of a flow of exhalation gas from, the airway of a patient may be used while remaining within the scope of the present invention. In the embodiment shown inFIG. 1, patient interface device8includes a cushion assembly12and a frame member14having a faceplate portion16and a forehead support portion18. Frame member14is made of a rigid or semi-rigid material, such as, without limitation, an injection molded thermoplastic or silicone. Straps (not shown) of a headgear component may be attached to faceplate portion16via attachment members20and to forehead support portion18via attachment members22to secure patient interface device8to the patient's head. An opening in faceplate portion16to which elbow conduit10is coupled allows the flow of breathing gas from pressure generating device4to be communicated to an interior space defined by faceplate portion16and cushion assembly12, and then, to the airway of a patient. The opening in faceplate portion16also allows the flow of exhalation gas (from the airway of such a patient) to be communicated to exhaust vent24provided in elbow conduit10.

FIG. 2is a side isometric view,FIG. 3is a front isometric view,FIG. 4is a front elevational view, andFIGS. 5 and 6are cross-sectional views of cushion assembly12according to one non-limiting exemplary embodiment of the present in invention. Cushion assembly12includes a cushion member26coupled to a support ring28. Support ring28is made from a rigid or semi-rigid material, such as, without limitation, an injection molded thermoplastic or silicone, and facilitates secure fluid connection of cushion assembly12to frame member14.

In the exemplary embodiment, cushion member26is defined from a unitary piece of soft, flexible, cushiony, elastomeric material, such as, without limitation, silicone or an appropriately soft thermoplastic elastomer, or any combination of such materials. It will be understood, however, that cushion member26does not need to be unitary within the scope of the present invention. Rather, cushion member26, and the parts thereof, may be made of separate components (e.g., separate sealing flap and support portion) that are coupled to one another by suitable means. Also in the exemplary embodiment, cushion assembly12has a generally triangular shape including a bottom region30, an apex region32located opposite bottom region30, a first side region34and a second side region36located opposite first side region34. As a result, both cushion member26and support ring28will have associated bottom, apex and first and second side regions.

Cushion member26includes an outer wall38comprising a support portion of cushion member26and a sealing flap40that extends inwardly from outer wall38. As seen inFIGS. 2-4, sealing flap40includes a proximal end42coupled to the top edge of outer wall38and a distal end44opposite proximal end42, wherein distal end44defines an opening46structured to receive the patient's nose. Sealing flap40thus extends in a direction that is transverse to a longitudinal axis48(FIG. 4) of cushion assembly12, wherein longitudinal axis48extends from the rear50of cushion assembly12where cushion assembly12attaches to frame member14to the front52of cushion assembly12(longitudinal axis48thus defines the general direction in which gasses flow through cushion assembly12).

In addition, in the exemplary embodiment, outer wall38extends outwardly from support ring28in a direction that is generally parallel to longitudinal axis48and generally perpendicular to the plane defining rear50of cushion assembly12. Sealing flap40thus extends in an angled (e.g. upwardly or downwardly with respect to the plane just described; in the illustrated embodiment, it extend upwardly), cantilevered fashion from the top edge of outer wall38such that when patient interface device8is donned by the user, the user's face (e.g., nose bridge, cheeks and area above the upper lip) will directly engage the top, outer surface54of sealing flap40to form a seal therewith. In one exemplary embodiment, the angle of sealing flap40may be upwardly/outwardly 85° from the plane defining rear50of cushion assembly12, to downwardly/inwardly −85° from the plane defining rear50of cushion assembly12.

In addition, sealing flap40of cushion member26includes a corrugated portion56, which is shown schematically inFIG. 7. In the illustrated, non-limiting exemplary embodiment, corrugated portion56is provided at the apex region of cushion member26such that it will be directly engaged by the nose bridge of the user. As used herein, and referring toFIG. 7, the term “corrugated portion” shall refer to a portion of sealing flap40that commences at distal edge44of sealing flap40(which defines the perimeter opening46) and that extends either partially or fully toward/to proximal edge42along the width of sealing flap40and that includes a series of alternating furrows58(also referred to as valleys) and ridges60(also referred to as peaks), wherein the corrugated portion56includes at least two furrows58and at least one ridge60, or at least one furrow58and at least two ridges60.

In particular embodiments, as described herein, corrugated portion56includes at least two furrows58and at least two ridges60. As seen inFIG. 7, corrugated portion56will have a lateral length l1measured at distal edge44and from point a (the beginning lateral side of corrugated portion56) to point b (the ending lateral side of corrugated portion56) that is longer than a lateral length l0of a prior art non-corrugated portion (represented by the dashed lines inFIG. 7) of a sealing flap that would extend between the same two points (a and b). Thus, corrugated portion56will increase the actual opening circumference of sealing flap40(it will create a longer arc length because l1>l0) without increasing its opening area or height/depth as compared to the prior art non-corrugated portion shown inFIG. 7.

In addition, the overall shape of corrugated portion56will be determined by the amplitude of each furrow58and each ridge60(which may be uniform or vary within corrugated portion56), the wavelength measured from the beginning of a ridges60to an immediately adjacent furrow58) (which may be uniform or vary within corrugated portion56), the radius of curvature of each furrow58and each ridge60(which may be uniform or vary within corrugated portion56), and the length of each furrow58and each ridge60(i.e., the distance each extends from distal edge44toward proximal edge42) (which may be uniform or vary within corrugated portion56). Thus, corrugated portion56may be used to increase the opening circumference of sealing flap40by any desired percentage, and the increase in circumference may be controlled by the amplitude, wavelength, and/or radii of the furrows58and ridges60that comprise the corrugated portion56. Furthermore, the length of each furrow58and each ridge60will control the possibility of leak paths, and in one embodiment, such lengths are made short enough to create a robust seal at and past the point on sealing flap40where furrows58and ridges60end. This all occurs without increasing or decreasing the flap height and without increasing or decreasing the area of the sealing flap opening, and will reduce pressure and red marks.

In one particular, non-limiting exemplary embodiment corrugated portions56may utilize a soft material having a durometer of 35 to 55 Shore 00, with a material thickness of 0.05 mm to 1 mm, with a furrow to ridge (immediately adjacent to one another) total amplitude range of 2 mm to 3 mm within the corrugated portions56, and with a wavelength (measured using immediately adjacent furrows and ridges) range of 4 mm to 5 mm within the corrugated portions56. As will be appreciated, this will result in a total amplitude to wavelength ratio (using immediately adjacent furrows and ridges) within corrugated portion56of 0.4 to 0.75. In one specific implementation, that ratio is 0.5 (1:2) throughout corrugated portion56. In addition, this embodiment may employ a ridge and furrow radii (radius of curvature) of 1 mm to 2 mm, with a furrow/ridge length of 11 mm to 13 mm. It will be understood, however, that in other embodiments other combinations of durometer, thickness, furrow/ridge length, amplitude, wavelength, and radii may be utilized. As material properties change, the relationship and ratios between the aforementioned specifications would be modified to achieve the same effect of increasing the circumference of the sealing flap opening by the corrugations elongating and flattening. As the materials used get softer, the thickness and amplitude of corrugated portions56may increase while decreasing wavelength and radii to achieve the desired effect.

As the materials used get harder, the thickness and amplitude may be decreased and the wavelength and radii may be increased for the desired effect. Combinations of these or other increasing and decreasing ratios may be utilized to optimize the desired effect of increasing the circumference of the sealing flap opening by the corrugations elongating and flattening. The properties of the materials chosen (most importantly durometer and elongation) will drive the ratio and relationship between the aforementioned geometry for optimization of increasing the circumference of the sealing flap opening by the corrugations elongating and flattening. A wider range of these properties and geometries may be: durometer 00 to 90 Shore 00, 0.2 mm to 2 mm for sealing flap thickness, ridge to furrow amplitude 1 mm to 10 mm, wavelength 1 mm to 8 mm, radii 0.05 mm to 5 mm, ridge/furrow length 1 mm to 30 mm. The ratio of total amplitude to wavelength would ideally be 1:2, but may vary to optimize the effect of increasing the circumference of the sealing flap opening by the corrugations elongating and flattening. It should be noted that these are not specifications or limitations to the invention geometry and that any combination or ratio thereof may be utilized for the invention. These would need to be optimized to optimize the effect of increasing the circumference of the sealing flap opening by the corrugations elongating and flattening.

Corrugated portion56is thus advantageous as it will allow cushion member26to automatically adjust to different facial depths and geometries. More specifically, corrugated portion56will readily conform to multiple facial geometries and depths in response to top outer surface54being engaged since corrugated portion56provides, at a focused location, additional flap length without increasing the height/depth of sealing flap58and without creating bunching. Furrows58and ridges60will conform against the user's face when it engages the top, outer surface54of sealing flap40, and will provide the additional stretch and flex needed for those with deeper features (e.g., deeper noses), yet will still seal against the face of those with shallower features (e.g., noses). Corrugated portion56thus eliminates the need for different designs and/or heights/depths to fit different nose depths and facial geometries.

Corrugated portion56also reduces the chances that sealing flap40will be too short on certain user faces and reduces the possibility of excess pressure and red marks because the sealing flap height does not need to be reduced for patients with shallower noses or other facial geometries.

Moreover, in the illustrated exemplary embodiment wherein corrugated portion56is provided at the apex region of cushion member26, corrugated portion56will minimize the compressive force (−z direction) at the nose bridge because of the depth of furrows58and ridges60at that localized area. As stated above, furrows58and ridges60will provide an arc length at the apex region of sealing flap40defining opening46that is longer and much more flexible and stretchable than a flap without corrugated portion56. As strapping force is applied to the patient interface device8, furrows58and ridges60will flatten out, thereby increasing the arc length and absorbing the force. Furrows58and ridges60, and the additional arc length and flex they provide, will also reduce the shear (+ and −x and y directions) across and up and down the nose bridge.

Corrugated portion56thus provides a dynamic sealing cushion solution. More particularly, as patient interface device8is tightened against the user's face, the amplitude of furrows58and ridges60will decrease, the wavelength of furrows58and/or ridges60will increase, the radii of furrows58and ridges60will increase, and the material of sealing flap40will stretch, with the end result being a continuous arc. The pressure and shear, however, are reduced, thereby reducing the potential for red marks as compared to traditional designs. Corrugated portion56absorbs the force and shear instead of the skin on the nose bridge. This is in contrast to a traditional, non-corrugated sealing flap which presses tighter against the nose and creates shear on the skin immediately upon contact between the flap and the face. Such a non-corrugated flap will immediately, upon contact and having −z direction force applied, begin to compress and shear against the skin because elongation and stretch of the sealing flap material is the sole feature to absorb force. In the present invention, it takes less force and causes less shear to flatten furrows58and ridges60until they are flush with the skin.

FIG. 8is a schematic illustration of a cushion assembly12-1according to an alternative particular, non-limiting exemplary embodiment. In cushion assembly12-1, corrugated portion56-1is constructed such that furrows58and ridges60are formed in an array on an arc wherein all of the furrows58and all of the ridges60have a common focal point62that is above the apex region of opening46.FIG. 9is a schematic illustration of a cushion assembly12-2according to another alternative particular, non-limiting exemplary embodiment. In cushion assembly12-2, corrugated portion56-2is constructed such that furrows58and ridges60are formed in an array on an arc wherein all of the furrows58and all of the ridges60have a common focal point64that is below the apex region of opening46. It will be understood, however, that corrugated portions56-1and56-2are exemplary only, and that furrows58and ridges60do not need to be formed in an array with a common focal point. Rather, in alternative embodiments, furrows58and ridges60may be straight, horizontal, vertical, or on an angle.

Furthermore, while in the embodiments shown inFIGS. 1-9, corrugated portion56is provided in the apex region of sealing flap40such that it will be engaged by the bridge of the user's nose, it will be understood that that is but one example implementation of the present invention and that a corrugated portion56may be provided in one or more other portions of sealing flap40(anywhere around sealing flap40). For example,FIG. 10is a schematic illustration of a cushion assembly12-3according to another particular, non-limiting exemplary embodiment wherein corrugated portion56-3is provided in the bottom region of sealing flap40such that it will be engaged by the portion of the patient mouth above the upper lip. In addition, in the non-limiting illustrated embodiment of cushion assembly12-3, corrugated portion56-3is constructed such that furrows58and ridges60are formed in an array on an arc wherein all of the furrows58and all of the ridges60have a common focal point (below the bottom region of opening46in the illustrated embodiment, although it may also be above the bottom region of opening46).

As another example,FIG. 11is a schematic illustration of a cushion assembly12-4according to yet another particular, non-limiting exemplary embodiment wherein corrugated portions56-4aand56-4bare provided in the side regions of sealing flap40such that they will be engaged by the cheeks of the patient. In addition, in the non-limiting illustrated embodiment of cushion assembly12-4, corrugated portions56-4aand56-4bare constructed such that furrows58and ridges60are formed in an array on an arc wherein all of the furrows58and all of the ridges60have a common focal point.FIG. 12is a schematic illustration of a cushion assembly12-5according to yet another particular, non-limiting exemplary embodiment that includes corrugated portions56in the apex, bottom and side regions of sealing flap40. Such corrugated portions56may be constructed such that furrows58and ridges60are formed in an array on an arc wherein all of the furrows58and all of the ridges60have a common focal point as described elsewhere herein.

In still another alternative, in theFIG. 12embodiment, the corrugated portions56in the side regions of sealing flap40may be omitted, leaving only the corrugated portions56in the apex and bottom regions of sealing flap40.FIG. 13is a schematic illustration of a cushion assembly12-6according to still another particular, non-limiting exemplary embodiment that includes corrugated portions56in the apex region, the bottom region, and in the portions of sealing flap40where the bottom region meets the side regions. Thus, in this embodiment, a corrugated portion56is provided at each part of the distal edge44of sealing flap40that is curved. Such corrugated portions56may be constructed such that furrows58and ridges60are formed in an array on an arc wherein all of the furrows58and all of the ridges60have a common focal point as described elsewhere herein.

Moreover, as seen inFIGS. 1-13, each of the corrugated portions56shown therein have arc-shaped (in cross-section) furrows58and ridges60such that corrugated portions56, in cross-section, resembles a sine wave. It will be understood, however, that the embodiments ofFIGS. 1-13including the particular geometry just described is meant to be exemplary only, and that other shapes for the furrows58and ridges60shown therein are also possible. For example,FIG. 14is a schematic illustration showing corrugated portions56′ that may be provided at curved (top ofFIG. 14; e.g., apex region of sealing flap40) or straight (bottom ofFIG. 14; e.g., side regions of sealing flap40) distal edge portions of sealing flap40, wherein the furrows58′ and ridges60′ have a v-shaped cross-section. As a result, corrugated portions56′, in cross-section, resemble a sawtooth wave.

As another example,FIG. 15is a schematic illustration showing corrugated portions56″ that may be provided at curved (top ofFIG. 15; e.g., apex region of sealing flap40) or straight (bottom ofFIG. 15; e.g., side regions of sealing flap40) distal edge portions of sealing flap40, wherein the furrows58″ and ridges60″ have squared off bottom portions. As a result, corrugated portions56″, in cross-section, resemble an angled square wave. As still another example,FIG. 16is a schematic illustration showing corrugated portions56′″ (superimposed for reference on a sinusoidal wave66similar to corrugated portions56having the shape shown inFIGS. 1-13and described above), that may be provided at curved (top ofFIG. 16; e.g., apex region of sealing flap40) or straight (bottom ofFIG. 16; e.g., side regions of sealing flap40) distal edge portions of sealing flap40. In this embodiment, corrugated portions56′″ follow a sinusoidal pattern wherein each peak68and valley70in the sinusoidal pattern includes a plurality of furrows58′″ and ridges60′″.