Abstract:
Various embodiments of respiratory patient interfaces that may be used to treat a variety of disorders involving upper airway obstruction, such as, without limitation, Obstructive sleep apnea (OSA), obstructive sleep hypopnea, and upper airway resistance syndrome (UARS). A number of the embodiments employ a nasal pillow assembly including a frame that supports a nasal pillow sleeve and a clip that is slid over a flange of the fame to couple the nasal pillow sleeve to the frame.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application is a Continuation of U.S. patent application Ser. No. 13/060,113, filed Feb. 25, 2011, which claims benefit under 35 U.S.C. §371 of International Application No. PCT/IB2009/053603 filed on Aug. 15, 2009, which claims the priority benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/091,551 filed on Aug. 25, 2008, the contents of which are herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to respiratory patient interfaces used to deliver a gas to a user, and in particular to various embodiments of respiratory patient interfaces that may be used to treat a variety of disorders involving upper airway obstruction. 
         [0004]    2. Description of the Related Art 
         [0005]    Obstructive sleep apnea (OSA), obstructive sleep hypopnea, and upper airway resistance syndrome (UARS) are among a variety of known disorders characterized by episodes of complete or partial upper airway obstruction during a state of diminished consciousness, such as sleep, anesthetization, or post anesthesia. OSA, hypopnea, and UARS cause intermittent interruption of ventilation during sleep with the consequence of potentially severe oxyhemoglobin desaturation. Typically, those afflicted with OSA, hypopnea, and UARS experience repeated, frequent arousal from sleep in response to the oxygen deprivation. The arousals result in sleep fragmentation and poor sleep continuity. 
         [0006]    Consequences of OSA, hypopnea, and UARS may include debilitating daytime sleepiness and cognitive dysfunction, systemic hypertension, cardiac dysrythmias, pulmonary arterial hypertension and congestive heart failure. Other consequences may include a predisposition to myocardial infarction, angina pectoris, stroke, right ventricular dysfunction with cor pulmonale, carbon dioxide retention during wakefulness as well as during sleep, and continuous, reduced arterial oxygen tension. Moreover, the cognitive impairment resulting from OSA, hypopnea, and UARS puts those afflicted at elevated risk of accidents. 
         [0007]    The pathogenesis of the airway obstruction that characterizes OSA, hypopnea, and UARS can include both anatomic and functional abnormalities of the upper airway that result in increased airflow resistance. Such abnormalities may include narrowing of the upper airway due to suction forces created during inspiration, the effect of gravity pulling the tongue back to appose the pharyngeal wall, and insufficient muscle tone in the upper airway dilator muscles, among others. It is also believed that excessive soft tissue in the anterior and lateral neck, as commonly observed in obese persons, can apply sufficient pressure to internal structures to narrow the upper airway and restrict air flow. 
         [0008]    Conventional treatment of OSA, hypopnea, and UARS has included surgical intervention, such as uvalopalotopharyngoplasty, gastric surgery for obesity, mandibular advancement procedures, maxillo-facial reconstruction, and tracheostomy. However, surgery potentially involves considerable risk of post-operative morbidity and mortality. In addition, the failure rate of surgery is disturbingly high. Pharmacological therapy has also been proposed to treat OSA, hypopnea, and UARS; however, results have been generally disappointing. 
         [0009]    More recently, various positive airway pressure therapies applied during sleep have been used to treat OSA, hypopnea, and UARS patients. During such treatment, positive pressure is applied in the upper airway to splint or support the airway open, thereby preventing its collapse and the resultant airway obstruction. A typical positive airway pressure device comprises a flow generator (e.g., a blower) that delivers gas via a delivery conduit to a patient interface, such as a mask or nasal pillow. It is also known to deliver the positive airway pressure therapy as a continuous positive airway pressure (CPAP), a variable airway pressure, such as a bi-level pressure that varies with the patient&#39;s respiratory cycle (Bi-PAP), or an auto-titrating pressure that varies with the monitored condition of the patient. Pressure support therapies are also provided to treat other medical and respiratory disorders, such as Cheynes-Stokes respiration, congestive heart failure, and stroke. 
         [0010]    Many patient interfaces are known in the art. These interfaces include nasal pillows with prongs which fit into the nares of the patient, nasal masks which fit over the patient&#39;s nose, nasal-oral masks that fit over the mouth and nose, and full face masks which fit over the patient&#39;s entire face. It is known to maintain such interfaces on the face of a patient by a headgear that wraps around the head of the patient. A typical headgear includes flexible, adjustable straps that extend from the nasal pillow and/or mask to attach it to the patient. 
         [0011]    For such devices to be effective, two competing goals need to be balanced: comfort and support. If the interface proves to be uncomfortable, patient compliance will be low. Comfort may be enhanced by reducing the area of contact between the interface and the patient and/or by using of a soft, lightweight, flexible material. In contrast, to enhance the ability of the interface to support its weight and associated hoses and attachments, the interface should ideally be constructed from a rigid material and have a large contact area between the interface and the patient. 
         [0012]      FIGS. 1 and 2  are isometric and exploded/disassembled views, respectively, of one prior art patient interface device  2  which attempts to balance the competing goals of comfort and support. The patient interface device  2  includes a headgear  4  and a nasal pillow assembly  6 . The headgear  4  includes rigid or semi-rigid yokes  8  which provide stability to the sides of the headgear  4 . In addition, the headgear  4  includes a headgear ring  9  having a seal ring  10  therein provided at the end of each yoke  8  for connecting the headgear to the nasal pillow assembly  6  as described below. 
         [0013]    As seen most readily in  FIG. 2 , the nasal pillow assembly  6  includes a frame  12  made of a rigid material such as, without limitation, a plastic material, which supports a pillow sleeve  14  made of a flexible material such as, without limitation, silicone. The frame  12  includes a flange portion  16  and connector portions  18  provided at each end of the frame  12 . The flange portion  16  includes vent holes  20  through which exhaled gasses may pass. The pillow sleeve  14  includes nasal prongs  22  structured to be partial received within the nares of the patient. Finally, the nasal pillow assembly  6  includes a clip  24  made of a rigid material such as, without limitation, a plastic material, the function of which is described below. 
         [0014]    The patient interface device  2  is assembled by first assembling the nasal pillow assembly  6  by wrapping the pillow sleeve  14  around the frame  12  in a manner such that each of the lipped ends  26  of the pillow sleeve  14  is received in a space formed between respective retaining flanges  28  and the flange  16 . Then, the clip  24  is slid over the flange  16  and the lipped ends  26  ( FIG. 1 ). As seen in  FIGS. 1 and 2 , the clip  24  includes a rectangular opening  30  which leaves the vent holes  20  exposed when the nasal pillow assembly  6  is assembled. Next, the headgear  4  is connected to the nasal pillow assembly  6  by inserting each of the connector portions  18  of the frame  12  through a respective one of the headgear rings  9  and seals rings  10 . Then, a cap  32  is inserted into one of the connector portions  18  and a tube assembly  34  having an elbow  36  is inserted into the other of the connector portions  18 . The positions of the tube assembly  34  and the plug  32  may be interchanged according to preference, e.g., the typical sleeping position of the patient. The tube assembly  34  is provided with a source of pressurized gas. 
         [0015]    Although the patient interface device  2  shown in  FIGS. 1 and 2  may have advanced the art, there is still room for improvement in the field of patient interface devices. Described herein are a number of improvements to patient interface devices such as, without limitation, the patient interface device  2 . 
         [0016]    In addition, a prior version of the patient interface device  2  exists which is similar in structure to the patient interface device  2 . The main difference between the two devices lies in the nasal pillow assembly of each. In particular, the nasal pillow assembly of the prior version includes a pillow sleeve that is similar to the pillow sleeve  14  of the patient interface device  2 , except that it includes a series of vent holes that are provided in front of the nasal prongs thereof. In addition, unlike the frame  12  and the clip  24  of the patient interface device  2  which have one or more holes provided therein, the frame and clip of the prior version are both solid. Thus, in the prior version, exhaled gasses are passed through the vent holes of the pillow sleeve rather then through the frame and clip. Patients using the prior version often switch to the patient interface device  2 , which may lead to certain problems relating component interchangeability as described elsewhere herein. In particular, patients or caregivers may attempt to use components, such as the frame and clip of one version with the remaining components of the other version, which can be problematic. 
       SUMMARY OF THE INVENTION 
       [0017]    In one embodiment, the present invention provides a patient interface device that includes a frame for supporting a flexible interface member that is structured to deliver a gas to an airway of a patient, and a clip structured to be coupled to the frame by sliding the clip onto a flange provided as part of the frame. The flange includes a first element and the clip includes a second element, wherein one of the first element and the second element is structured to be received within the other of the first element and the second element when the clip is slid onto the flange to permit the clip to be fully slid onto the flange. If the first and second elements do not mate in this manner, the clip will not be able to be fully slid onto the flange. As a result, incompatible clips are discouraged from being used with the frame. 
         [0018]    In another embodiment, the invention provides a patient interface device that includes a frame having a flange extending along a longitudinal axis of the frame, and an integrated interface assembly that includes a flexible interface member and a clip member affixed to the flexible interface member. The flexible interface member, such as a nasal pillow sleeve, is structured to deliver a gas to an airway of a patient. The flexible interface member is also structured to be at least partially wrapped around the frame and the clip member is structured to be snapped over the flange to couple the integrated interface assembly to the frame. 
         [0019]    In yet another embodiment, the invention provides a patient interface device that includes an interface assembly structured to deliver a gas to an airway of a patient, wherein the interface assembly has an end portion which defines an opening. The patient interface device also includes an end cap having a post portion and an end portion. The post portion is received within the opening of the interface assembly and the end portion is structured to permit exhaled gases to flow therethrough. 
         [0020]    In still another embodiment, the invention provides a patient interface device that includes an interface assembly structured to deliver a gas to an airway of a patient and that includes an end portion which defines an opening. The patient interface device further includes a tube assembly for delivering the gas to the interface assembly. The tube assembly is coupled to the interface assembly through the opening therein and includes an exhaust portion structured to permit exhaled gases to flow therethrough. 
         [0021]    In yet another embodiment, the invention provides a patient interface device that includes a nasal pillow assembly having a frame and a flexible pillow sleeve coupled to the frame. The nasal pillow assembly is structured to deliver a gas to an airway of a patient. The patient interface device also includes a headgear coupled to the nasal pillow assembly. The headgear includes a first side yoke coupled to a first side of the frame and a second side yoke coupled to a second side of the frame. Also included is a first cheek stabilizer attached to an interior of the first side yoke and a second cheek stabilizer attached to an interior of the second side yoke. 
         [0022]    In still a further embodiment of the invention, a patient interface device is provided that includes a nasal pillow assembly having a frame and a flexible pillow sleeve coupled to the frame, wherein the nasal pillow assembly is structured to deliver a gas to an airway of a patient. The flexible pillow sleeve has a first nasal prong, a second nasal prong, and a stabilizer provided between the first and second nasal prongs. The stabilizer is structured to engage the patient&#39;s face at a location above the patient&#39;s upper lip and below the patient&#39;s nose. 
         [0023]    In still a further embodiment, the invention provides a patient interface device that includes a flexible nasal pillow sleeve having a first nasal prong and a second nasal prong for delivering a gas to an airway of a patient. The flexible nasal pillow sleeve includes at least one integral stiffening member. In addition, the patient interface device includes a first connecting portion attached to a first end of the flexible nasal pillow sleeve and a second connecting portion attached to a second end of the flexible nasal pillow sleeve. The first connecting portion and the second connecting portion are each structured to receive either an end cap or a tube assembly therein. The device further includes a headgear having a first yoke coupled to the first connecting portion and a second yoke coupled to the second connecting portion. 
         [0024]    In another alternative embodiment, the invention provides a patient interface device that includes a frame having a flange, a flexible nasal pillow sleeve supported by the frame that includes first and second nasal prongs for delivering a gas to an airway of a patient, and a clip coupled to the frame by sliding the clip over the flange. The clip, when slid in this manner, couples the flexible nasal pillow to the frame. The device also includes a chin support assembly coupled to the flexible nasal pillow sleeve that is structured to support the patient&#39;s chin. 
         [0025]    In yet another embodiment, the invention provides a patient interface device that includes a nasal pillow sleeve having a first nasal prong and a second nasal prong for delivering a gas to an airway of a patient, a tube assembly operatively coupled to the nasal pillow sleeve for delivering the gas to the nasal pillow sleeve, and a tube management device having a first end and a second end. The first end of the tube management device is coupled to the nasal pillow sleeve and is positioned between the first and second nasal prongs, and the second end of the tube management device is coupled to and supports the tube assembly. As a result, a majority of the tube assembly is positioned generally in a center of and below the nasal pillow sleeve when the device is worn by the patient. 
         [0026]    Another embodiment provides a patient interface device that includes a nasal pillow assembly structured to deliver a gas to an airway of a patient, wherein the nasal pillow assembly includes a frame having a flange, a flexible nasal pillow sleeve supported by the frame and having first and second nasal prongs, and a clip coupled to the frame by sliding the clip over the flange. The device further includes an oral member, such as a bite block, that is coupled to the nasal pillow assembly and that is structured to be received within the patient&#39;s mouth. 
         [0027]    In yet another embodiment, the invention provides a patient interface device that includes a nasal pillow assembly for delivering a gas to an airway of a patient, wherein the nasal pillow assembly includes a cushion portion having first and second nasal prongs that is attached to a frame portion. The device further includes a tube assembly coupled to the frame portion and in fluid communication with the nasal pillow assembly. The tube assembly is selectively slideable along the frame portion in a manner which maintains the fluid communication with the nasal pillow assembly in an airtight manner. 
         [0028]    Therefore, it should now be apparent that the invention substantially achieves all the above aspects and advantages. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Moreover, the aspects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
         [0029]    The accompanying drawings illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain the principles of the invention. As shown throughout the drawings, like reference numerals designate like or corresponding parts. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]      FIGS. 1 and 2  are isometric and exploded/disassembled views, respectively, of one particular prior art patient interface device; 
           [0031]      FIG. 3  is a top plan view of a clip and  FIG. 4  is a top plan view of a frame according to an embodiment of the invention; 
           [0032]      FIG. 5  is a top plan view of a clip and  FIGS. 6 and 7  are side elevational and top plan views, respectively, of a frame according to another embodiment of the invention; 
           [0033]      FIG. 8  is an isometric view of a clip and  FIG. 9  is an isometric view of an integrated pillow sleeve assembly according to another embodiment of the invention; 
           [0034]      FIG. 10  is a cross-sectional view of the clip of  FIG. 9  coupled to the frame of  FIG. 8 ; 
           [0035]      FIG. 11  is an isometric view of an end cap according to one particular embodiment, and  FIG. 12  is an isometric view of an end cap according to another particular embodiment; 
           [0036]      FIG. 13  is a side elevational view demonstrating airflow through the end caps shown in  FIGS. 11 and 12 ; 
           [0037]      FIG. 14  is a side elevational view and  FIG. 15  is an isometric view of an end cap according to an alternative embodiment; 
           [0038]      FIGS. 16-18  are isometric, front and rear views, respectively, of a gas deflector according to a further embodiment of the invention, and  FIG. 19  is a side elevational view showing the gas deflector coupled to an end cap; 
           [0039]      FIGS. 20A and 20B  are isometric and side elevational views, respectively, of an end cap according to still a further embodiment of the invention; 
           [0040]      FIGS. 21A and 21B  are isometric and side elevational views, respectively, of an end cap according to yet a further alternative embodiment of the invention; 
           [0041]      FIG. 22  is an isometric view of a tube assembly according to a further embodiment of the invention; 
           [0042]      FIG. 23  is an isometric view of a headgear according to yet another alternative embodiment; 
           [0043]      FIG. 24  is a top plan view, and  FIG. 25  is a side elevational view of a pillow sleeve according to yet another embodiment of the invention; 
           [0044]      FIGS. 26 ,  27  and  28  are front elevational views of various embodiments of a bendable and formable pillow sleeve according to a further aspect of the invention; 
           [0045]      FIG. 29  is a front elevational view and  FIG. 30  is a side elevational view of a patient interface device according to a further embodiment of the invention; 
           [0046]      FIG. 31  is a front elevational view and  FIG. 32  is a side elevational view of a patient interface device according to yet another alternative embodiment; 
           [0047]      FIG. 33  is a side elevational view of a tube management device according to yet another embodiment of the invention; 
           [0048]      FIG. 34  is a front elevational view of a patient interface device which incorporates the tube management device shown in  FIG. 33 ; 
           [0049]      FIG. 35  is an isometric view of a patient interface device according to yet a further alternative embodiment of the invention; 
           [0050]      FIG. 36  is an alternative embodiment of a patient interface device that is similar to the patient interface device shown in  FIG. 35 ; 
           [0051]      FIG. 37  is an isometric view of yet a further alternative embodiment of a patient interface device that includes an oral member; 
           [0052]      FIG. 38  is a front elevational view of the patient interface device shown in  FIG. 37  being worn by a patient; 
           [0053]      FIG. 39  is an isometric view showing a nasal pillow assembly according to still a further embodiment; 
           [0054]      FIG. 40  is an isometric view of a patient interface device according to yet a further alternative embodiment of the invention; and 
           [0055]      FIGS. 41 and 42  shown one embodiment for implementing the sliding tube assembly forming part of the patient interface device shown in  FIG. 40 . 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0056]    Directional phrases used herein, such as, for example and without limitation, top, bottom, left, right, upper, lower, front, back, and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein. 
         [0057]    As employed, herein, the statement that two or more parts or components are “coupled” together shall mean that the parts are joined or operate together either directly or through one or more intermediate parts or components. 
         [0058]    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. 
         [0059]    As employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality). 
         [0060]    The present invention provides a number of modifications to patient interface devices employing a nasal pillow such as the patient interface device  2  shown in  FIGS. 1 and 2  and/or the prior version thereof described elsewhere herein. Such modifications and/or improvements include modifications to certain of the components thereof and/or variations of the patient interface device as a whole. The various modifications and/or improvements are described in detail below in connection with  FIGS. 3 through 42 . 
         [0061]      FIG. 3  is a top plan view of a clip  40  and  FIG. 4  is a top plan view of a frame  42  that may be used in connection with the patient interface device  2  or a similar device as a substitute for the clip  24  and the frame  12 . As seen in  FIG. 4 , the frame  42  includes connecting portions  44  and a flange  46 . The clip  40  is structured to be slid over the flange  46  after a pillow sleeve such as, without limitation, the pillow sleeve  14  is wrapped around the frame  42  in a manner similar to the manner described in connection with the patient interface device  2 . As seen in  FIG. 3 , the clip  40  includes a plurality of vent holes  48  provided on a top face  50  thereof. In addition, the flange  46  of the frame  42  includes a generally rectangular shaped opening  52  therein. Thus, when a nasal pillow assembly is assembled using the frame  42 , the clip  40  and a pillow sleeve such as the pillow sleeve  14  shown in  FIGS. 1 and 2 , exhaled gasses may be vented through the vent holes  48  and the opening  52 . As will be appreciated, the clip  40  may suitably be used with the pillow sleeve  14  and the clip  12  having vent holes  20  provided therein as shown in  FIG. 2  and with the prior version of the patient interface device  2  which includes a pillow sleeve having vent holes provided therein and a solid frame. 
         [0062]      FIG. 5  is a top plan view of a clip  54  which is structured to be used in combination with a frame  56  shown in  FIGS. 6 and 7 . In particular, as described in more detail below, the clip  54  and the frame  56  are provided with a mechanism that ensures that only the clip  54  may be used with the frame  56  so as to avoid a mismatch of components. As seen in  FIG. 5 , the clip  54  includes a generally rectangularly shaped opening  58  provided on a front face  60  thereof. Alternatively, the opening  58  may be replaced with a plurality of vent holes similar to the vent holes  48  shown in  FIG. 3 . In addition, a first end  62  is provided with a generally rectangularly shaped notch  64 . Referring to  FIGS. 6 and 7 , the frame  56  includes connector portions  66  and a flange  68  having a plurality of vent holes  70  provided therein. Alternatively, the vent holes  70  may be replaced by a generally rectangularly shaped opening similar to the opening  52  shown in  FIG. 4 . In addition, the flange  68  has a generally rectangularly shaped post  72  extending from a top surface thereof. The shape of the post  72  is structured to match the shape of the notch  64 . Thus, when the clip  54  is slid onto the flange  68  after a pillow sleeve such as a pillow sleeve  14  has been wrapped around the clip  56 , the post  72  will be received within the notch  64  so that the clip  54  may be slid all the way in place on the frame  56 . As will be appreciated, if a clip not having a notch  64  is attempted to be slid onto the frame  56 , it will not be able to be slid completely thereon due to interference provided by the post  72 . As a result, the provision of the notch  64  and the post  72  ensure that only the clip  54  (or a similarly structured clip) may be properly slid onto the flange  68  during the assembly of a patient interface device that incorporates the frame  56 , thereby preventing a mismatch of components (i.e., the use of another, non-matching clip). 
         [0063]      FIG. 8  is an isometric view of a clip  74  structured to be used in conjunction with an integrated pillow sleeve assembly  76  as shown in  FIG. 9 . The frame  74  is similar to the frame  12  shown in  FIGS. 1 and 2  in that it includes connector portions  78  and a flange  80  having a plurality of vent holes  82  provided therein. One problem that is associated with the frame  12  shown in  FIGS. 1 and 2  is that a solid clip, such as the clip provided with the prior version of the patient interface device  2  described elsewhere herein, may also be used in combination with the frame  12 . This presents a potentially dangerous condition because if the pillow sleeve  14 , which does not include any vent holes therein, is wrapped around the frame  12  and a prior solid clip is used instead of the clip  24  shown in  FIGS. 1 and 2 , the resulting assembly will not include any means for escape of exhalation gases as the solid clip will close and cover the vent holes  20  provided in the frame  12 . Thus, when a pillow sleeve such as the pillow sleeve  14  not having vent holes provided therein is intended to be used with a frame having vent holes provided therein, it is desirable to provide a mechanism which prevents the improper use of a non-compatible clip such as a solid clip therewith. 
         [0064]    The use of such an improper clip is discouraged according to one embodiment of the present invention by providing the integrated pillow sleeve member  76  shown in  FIG. 9 . In particular, the integrated pillow sleeve member  76  includes a pillow sleeve portion  79  which includes nasal prongs  80  and which is similar in structure to the pillow sleeve  14  shown in  FIGS. 1 and 2 . However, the integrated pillow sleeve member  76  also includes an integral clip member  82  that is provided as a part thereof. The integral clip member  82  may be affixed to the pillow sleeve portion  79  to form the integrated pillow sleeve member  76  in any of a number of known manners. For example, and without limitation, the pillow sleeve portion  79  may be over molded onto the clip member  82 , the pillow sleeve portion  79  may be affixed to the clip member  82  by an adhesive (such as a glue material), or the pillow sleeve portion  78  may be affixed to the clip member  82  by a suitable mechanical attachment mechanism. During assembly, the integrated pillow sleeve member  76  is wrapped around the frame  74  in a manner such that the clip member  82  is received between the upstanding end portions  84  of the clip  74  and is snapped over the flange  80  as shown in  FIG. 10 , which is a cross-sectional view showing the integrated pillow sleeve member  76  and a frame  74  assembled together. The clip member  82  of the integrated pillow sleeve member  76  includes a generally rectangular shaped opening  86  which, in combination with the vent holes  82  of the frame  74 , allows exhaled gasses to escape from a patient interface device that incorporates the assembly shown in  FIG. 10 . Because the clip  74  and the integrated pillow sleeve member  76  requires the clip member  82  to be snapped over the flange  80  of the frame  74 , users will not think about using a sliding member in any patient interface device that includes these components. Thus, as a result, it is unlikely that a user will mistakenly try to use a solid clip in any patient interface device intended to employ the clip  74 . In addition, the upstanding end portions  84  further discourage the use of a sliding clip with the frame  74 . In particular, if the height of the upstanding end portions  84  is made large enough (larger than the height of the non-compatible clip), the non-compatible clip will not be able to be slid over the flange  80  even if a user were to attempt to do so. Furthermore, the ability to snap a non-compatible clip such as a solid clip over the flange  80  may be limited by making the dimension  88  shown in  FIG. 10  larger than the internal height of such an incompatible clip (as a result, even if attempted, the clip will not be able to be snapped over the flange  80  when a pillow sleeve such as pillow sleeve  14  is wrapped thereover). As a result, any or all of these mechanisms help to ensure that only the integrated pillow sleeve member  76  will be used in connection with the frame  74 , thereby avoiding potentially dangerous combinations of incompatible components. In addition, it would be undesirable and potentially dangerous for the integrated pillow sleeve member  76  to be used with a solid frame as described elsewhere herein that does not include any vent holes or openings as such a combination would provide no means for exhaled gasses to escape. Therefore, it is desirable to make the integrated pillow sleeve member  76  in a manner that would discourage its use with such a frame. This may be done by making the internal height of the clip member  82  small enough such that it cannot be fit over the flange of the incompatible frame. The internal height is shown in  FIG. 9  with reference numeral  90 . 
         [0065]    As described elsewhere herein, the patient interface device  2  shown in  FIGS. 1 and 2  employs a cap  32  which is structured to be inserted through the headgear ring  9 , the seal ring  10 , and the connector portion  18  when the patient interface device  2  is assembled.  FIG. 11  is an isometric view of an end cap  92  according to one embodiment of the present invention. The end cap  92  includes a hollow post portion  94  that is adapted to be received within a connector portion such as, without limitation, a connector portion  18  of the patient interface device  2  (and through the headgear ring  9  and seal ring  10  thereof). The end cap  92  also includes an end portion  96  attached to the post portion  94 . The end portion  96  includes a plurality of vent holes  98  provided therein which are in fluid communication with the interior of the post portion  94 . Thus, when the end cap  92  is inserted into a connector portion such as the connector portion  18  of the patient interface device  2 , patient exhaled gasses are able to vented through the vent holes  98 . As will be appreciated, use of the end cap  92  allows the remaining portions of the patient interface device with which it is used to be solid (i.e., do not have any vent holes or openings therein). In particular, the end cap  92  may be used with the pillow sleeve  14  shown in  FIGS. 1 and 2  in conjunction with a solid frame and a solid clip (i.e., from the prior version), because the end cap  92  provides the means through which patient exhaled gasses may escape.  FIG. 12  is an isometric view of an alternative end cap  100  according to an alternative embodiment of the invention. The end cap  100  includes a hollow post portion  102  and an end portion  104 . The end portion  104  is made at least partially from a porous material  106  that allows gasses to be passed from the interior of the post portion  102  through the end portion  104 . The porous material or media  106  may be, for example, porous Polypropylene, porous High Density Polyethylene (HDP), porous Ultra-High Molecular Weight Polyethylene (UHMWP), porous PTFE, porous PDDF, or other suitable porous materials. Example suitable materials are available from Porex Corporation of Fairburn, Ga. Any suitable porous membrane product will be acceptable. 
         [0066]      FIG. 13  demonstrates the direction of flow of exhalation gasses when either the end cap  92  or the end cap  100  is employed in patient interface device such as, without limitation, the patient interface device  2 . 
         [0067]      FIG. 14  is a side elevational view and  FIG. 15  is an isometric view of an end cap  108  according to a further alternate embodiment of the present invention. The end cap  108  includes a hollow post portion  110  and a bulbous end portion  112 . The end portion  112  includes a plurality of vent holes  114  that are in fluid communication with the interior of the post portion  110  in order to allow exhaled gasses to pass from the interior of the end portion  110  through the vent holes  114 . The bulbous nature of the end portion  112  provides for improved diffusion of gas flow as compared to the end portions  96  and  104  shown in  FIGS. 11 and 12 . In particular, the flow of exhalation gasses, as shown in  FIG. 14 , is directed in a number of directions that intersects the longitudinal axis of the post portion  110 . In fact, in the embodiment shown in  FIG. 14 , exhaled gasses are, as indicated by the arrows, able to flow in a hemispherical pattern over a span of more than 180 degrees with respect to the longitudinal axis of the end portion  110 . This is in contrast to the flow of exhaled gasses shown in  FIG. 13 , which flow is substantially parallel to the longitudinal axis of the post portion  94 , 102 , as the case may be. As a result, the flow of exhaled gasses when the end cap  108  is employed is not as concentrated in a particular direction as in when end cap such as end cap  92  or  100  is used. Such a concentrated flow of exhaled gasses can, in some circumstances, be problematic as it may be undesirably directed at, for example, the patient&#39;s ear or at the bed partner of the patient. 
         [0068]      FIGS. 16 ,  17  and  18  are isometric, front elevational, and rear elevational views of an embodiment of a gas deflector  116  according to a further aspect of the present invention. As seen in  FIG. 16-18 , the gas deflector  116  includes a deflector body  118 , and legs  120  which define a receiving slot  122 . As shown in  FIG. 19 , the gas deflector  116  is structured to be mounted on an end cap such as end cap  92  or  100  in order to advantageously deflect the exhaled gasses being emitted through the end cap  92 , 100  in a desired direction as indicated by the arrows shown in  FIG. 19 . In particular, the end of the post portion  94 , 102  is structured to be received within the receiving slot  122  of the gas deflector  116 . When so received, the legs  120  will be positioned between the end portion  98 , 104  and the connecting portion of a frame in which it is inserted. The gas deflector  116  may be selectively positioned about the outer periphery of the end cap  92 , 100  in order to cause the deflector body  118  to selectively deflect the flow of gas in a desired direction. As a result, the flow of gas may be selectively directed away from a body part of the patient, such as the patient&#39;s ear, and/or the patient&#39;s bed partner. 
         [0069]      FIGS. 20A and 20B  show an alternative end cap  124  according to an alternative embodiment of the present invention. The alternative end cap  124  includes a first portion  126  structured to be received within a connecting portion of a frame, such as the connecting portion  118  of the frame  12  or any other connecting portion of a frame described elsewhere herein. A rotatable end portion  128  is rotatably attached to the post portion  126  in a manner which allows the end portion  128  to be selectively located relative to the longitudinal axis of the post portion  126  while maintaining an airtight seal between the end portion  128  and the post portion  126 . The end portion  128  is provided with a plurality of vent holes  130  along a selected, limited portion thereof. The vent holes  130  are in fluid communication with the interior of the post portion  126  and allow exhaled gasses to flow from the interior of the post portion  126  through the vent holes  130 . A user, by selectively locating the end portion  126 , is able to selectively direct the direction of flow of the exhaled gas as shown in  FIG. 20B . In the embodiment shown in  FIGS. 20A and 20B , the end portion  128  has a generally cylindrical shape.  FIGS. 21A and 21B  show an alternative embodiment of an end cap  124 ′ which is similar to the end cap  124  except that the end portion  128 ′ of the end cap  124 ′ is generally dome shaped. Like the end portion  128 , the end portion  128 ′ of the end cap  124 ′ is able to be selectively rotated in order to selectively direct the flow of exhaled gas as shown in  FIG. 21B . 
         [0070]    Referring to  FIG. 22 , an isometric view of a tube assembly  132  according to a further embodiment of the present invention is shown. The tube assembly  132  includes a gas delivery tube  134 , and elbow portion  136 , and a post portion  138  which is adapted to be received within a connecting portion of frame, such as the connecting portion  18  of the frame  12  or another connecting portion of a frame described elsewhere herein. As seen in  FIG. 22 , the elbow portion  136  of the tube assembly  132  includes a plurality of vent holes  140 . The vent holes  140  are in fluid communication with the interior of the post portion  138  and allow exhaled gasses to pass therethrough. As a result, as was the case with the end caps  92 , 100 , 108 , 124  and  124 ′, the elbow portion  136  may be used with a pillow sleeve, a frame, and a clip that are solid and contain no vent holes. 
         [0071]    Referring to  FIG. 23 , a headgear  142  according to a further embodiment of the present invention is shown. The headgear  142  is similar to the headgear  4  shown in  FIGS. 1 and 2 , except that it includes cheek stabilizers  144  on the interior of the yokes  146  thereof. Preferably, the cheek stabilizers  144  are in the form of a soft pad such as, without limitation, a silicone gel or polyurethane gel pad. When the headgear  142  is worn by a patient, the cheek stabilizers  144  are structured to be in contact with the patient&#39;s cheeks in order to stabilize the headgear  142  in place and reduce the strapping forces that are necessary to hold a nasal pillow assembly such as a nasal pillow assembly  6  or any other suitable nasal pillow assembly as described herein in place. Preferably, as shown in  FIG. 23 , the cheek stabilizers  144  have a circular or oblong disc shape. 
         [0072]      FIG. 24  is a top plan view and  FIG. 25  is a side elevational view of a pillow sleeve  148  according to yet another embodiment of the present invention that may be used in connection with a frame and clip as described herein, such as, without limitation, the frame  12  and the clip  24  shown in  FIGS. 1 and 2 . The pillow sleeve  148  shown in  FIGS. 24 and 25  includes nasal prongs  150  and an upper lip stabilizer  152  provided between and below the nasal prongs  150 . Preferably, the upper lip stabilizer comprises a soft pad made from, for example, a silicone gel or polyurethane gel material. Using either/or cheek stabilizers  144  and the upper lip stabilizer  152  may allow the rigid portions of the yokes  146  to be eliminated, thereby allowing the entire headgear  142  to be made of a soft, flexible material. The upper lip stabilizer is structured to be positioned beneath the nose and above the upper lip when an assembly employing the pillow sleeve  148  is worn. 
         [0073]      FIGS. 26 ,  27  and  28  shows various embodiments of a pillow sleeve that is bendable and formable according to a further aspect of the invention. The pillow sleeves shown in  FIGS. 26 ,  27  and  28  may be utilized without a frame and a slide, such as the frame  12  and the slide  24 . In particular,  FIG. 26  shows a pillow sleeve  154  that includes nasal prongs  156  and connecting portions  158  attached thereto. In addition, the pillow sleeve  154  further includes an integrated stiffening member  160  that is preferably bendable and formable. The stiffening member may be, for example and without limitation, a metal or plastic material that is over molded with the pillow sleeve  154 , attached to the pillow sleeve  154  using a suitable adhesive, or inserted within a pocket provided in the pillow sleeve  154 . The connecting portions  158  are preferably made of a rigid material and may be over molded with the pillow sleeve  154 , attached to the pillow sleeve  154  with a suitable adhesive, or otherwise attached to the pillow sleeve  154  using a suitable mechanical attachment mechanism. The connecting portions  158  are structured to be able to receive any one of the end caps  32 , 92 , 100 , 124  or  124 ′. In addition, the connecting portions  158  are also structured to be able to receive the tube assembly  34  or the tube assembly  132  shown in  FIG. 22 . The stiffening member  160 , in addition to providing sufficient rigidity to eliminate the need for a frame and a slide, also makes the nasal pillow  154  bendable and formable so as to be able to custom adjust the angle of the nasal prongs  156 .  FIG. 27  is an alternate embodiment of a pillow sleeve  154  that includes a vertically oriented stiffening member  160 , and  FIG. 28  is an embodiment of a pillow sleeve  154 ″ that includes multiple stiffening members  160 . 
         [0074]      FIG. 29  is a front elevational view and  FIG. 30  is a side elevational view a patient interface device  162  according to a further embodiment of the invention. The patient interface device  162  includes, in the particular embodiment shown, a nasal pillow assembly  164  that is similar to the nasal pillow assembly  6  shown in  FIGS. 1 and 2 . The nasal pillow assembly  164  includes a pillow sleeve  166  having nasal prongs  168 , a frame  170 , and a clip  172 . Although a frame  170  and a clip  172  similar to the frame  12  and clip  24  shown in  FIGS. 1 and 2  are shown in this particular embodiment, it should be understood that this is not meant to be limiting and that other frames and/or clips as described elsewhere herein may be used as desired. A tube assembly  174  is inserted within a connecting portion  176  of the frame  170  and an end cap  178  is inserted within the other connecting portion  176  of the frame  170 . The end cap  178  may either similar to the end cap  32  shown in  FIGS. 1 and 2 , or any of the end caps  92 , 100 , 108 , 124  or  124 ′. In addition, the patient interface device  162  includes a chin support assembly  180  including a rigid body having arms  182 . A chin support strap  184  is inserted through a pair of apertures  186  for supporting the chin of the patient, and a headgear strap  188  is inserted through apertures  190  and is structured to wrap around the head of the patient to help support the patient interface device  162 . The nasal pillow assembly  164  is attached to the chin support assembly  180  by way of a rigid connector  192 . Preferably, the rigid connector is molded as part of the body of the chin support assembly  180  and is attached to the pillow sleeve  166  of the nasal pillow assembly  164  using a suitable mechanism, such as over molding, an adhesive, or some other mechanical attachment mechanism. As seen in  FIGS. 29 and 30 , gas is delivered to the patient interface device  162  through the tube assembly  174  in a manner similar to the manner in which gas is delivered to the patient interface device  2  through the tube assembly  34  shown in  FIGS. 1 and 2 . In an alternative embodiment, the chin support strap  184  may be replaced by a rigid chin support member that forms a part of the chin support assembly  180 . 
         [0075]      FIG. 31  is a front elevational view and  FIG. 32  is a side elevational view of a patient interface device  162 ′ that is similar to the patient interface device  162  shown in  FIGS. 31 and 32 , except that instead of gas being delivered thereto by way of a tube assembly  174  that is similar to the tube assembly  34 , gas is delivered thereto by a tube assembly  194  that includes a rigid main tube and support mechanism  196  that is connected to a main supply tube  198 , and a tube assembly branch  200  which is in fluid communication with the main tube and support mechanism  196  at one end thereof and the nasal pillow assembly  164  at the opposite end thereof. As seen in  FIG. 32 , in this embodiment of the patient interface device  162 ′, arms  182  extend from the main tube and support mechanism  196 . 
         [0076]    As noted elsewhere herein, when a patient assembles the patient interface device  2  shown in  FIGS. 1 and 2 , the patient must decide on which side to place the tube assembly  34 . Typically, the patient uses one side or the other depending upon which side of the body the user prefers to sleep on. As will be appreciated, once the user makes this choice and places the patient interface device  2  on his or her head, the user&#39;s ability to sleep on the other side of his or her body is limited (the tube assembly  34  will get in the way if the user switches to sleeping on the other side).  FIG. 33  is a side elevational view of a tube management device in the form of an S-shaped hook  202  which enables a patient to simply and easily position the tube assembly  34  in the center of his or her body. The hook  202  includes a first end  204  and a second end  206 . Preferably, the hook  202  is made from a rigid or semi-rigid material such as, without limitation, metal or plastic. As seen in  FIG. 34 , the user hooks the first end  204  around the center of the nasal pillow assembly  6  in between the nasal prongs  22 . The user then positions the tube assembly  34  so that it is supported by the second end  206  of the hook  202 . As seen in  FIG. 34 , this will result in the majority of the tube assembly  34  being positioned generally in the center of and below the patient interface device  2  and therefore in the center of the patient&#39;s body when the patient interface device  2  is worn by the patient. As shown by the arrows in  FIG. 34 , the hook  202  may be selectively slid from side-to-side on the nasal pillow assembly  6  in order to selectively position the hook  202  and therefore the tube assembly  34 . Furthermore, although the hook  202  has been demonstrated in connection with the patient interface device  2 , it should be understood that this is meant to be exemplary only, and not limiting, and that the hook  202  may be used in connection with other patient interface device embodiments such as the various embodiments described elsewhere herein. 
         [0077]      FIG. 35  is an isometric view of a patient interface device  208  according to a further alternative embodiment of the present invention. The patient interface device  208  includes a nasal pillow assembly  210  that is similar to the nasal pillow assembly  6  shown in  FIGS. 1 and 2 . The nasal pillow assembly  210  includes a pillow sleeve  212  having nasal prongs  214 . The nasal pillow assembly  210  also includes a frame  216  and a clip  218  that are similar to the frame  12  and clip  24  shown in  FIGS. 1 and 2 . A tube assembly  220  is attached to one side of the nasal pillow assembly  210 , and an end cap  222  is attached to the opposite side of the nasal pillow assembly  210 . The nasal pillow assembly  210  is supported by a chin support assembly  224  that includes arms  226 , chin support strap  228  and headgear strap  230 . The patient interface device  208  further includes an oral member  232 , which in the particular embodiment shown in  FIG. 35  comprises a bite block inserted within the patient&#39;s mouth and held between the patient&#39;s teeth. The oral member  232  is attached to the chin support assembly  224  through a connecting member  234  which may be rigid or flexible. The oral member  232  provides additional stability to the patient interface device  208  when worn by the patient. The connecting member  224  may, in one embodiment, comprise a gas flow passage that is in fluid communication with the nasal pillow assembly  6  in order to receive gas therefrom. In such an embodiment, the oral member  232  would include an opening to allow the supplied gas to enter the patient&#39;s mouth and thereafter the patient&#39;s airway. 
         [0078]      FIG. 36  is an alternate embodiment of a patient interface device  208 ′ that is similar to the patient interface device  208  except that it includes a tube assembly  194  that is shown in  FIG. 31  for the delivery of the gas to the nasal pillow assembly  210 . Furthermore, although a nasal pillow assembly  210  that is similar to the nasal pillow assembly  6  is shown in  FIGS. 35 and 36 , it should be understood that this is meant to be exemplary only, and not limiting, and that other nasal pillow assemblies such as those shown elsewhere herein may be employed.  FIG. 37  shows a further alternative embodiment of a patient interface device  236  that includes an oral member  232  as shown in  FIGS. 35 and 36  but does not include the chin support mechanism  224 . Instead, as shown in  FIG. 37 , headgear  4  having yokes  8  is provided (for ease of illustration, only one yoke  8  is shown in  FIG. 37 ). Again, the oral member  232  provides added stability for the patient interface device  236 .  FIG. 38  is a front view of the patient interface device  236  shown being worn by a patient. As seen in  FIG. 38 , the nasal prongs  214  are received within the patient&#39;s nose and the oral member  232  is received within the patient&#39;s mouth. In addition, as shown in  FIG. 38 , the connecting member  234  is adapted to be bent in order to be selectively positioned for a comfortable fit. 
         [0079]    Patients which use patient interface devices such as, without limitation, the patient interface device  2  shown in  FIGS. 1 and 2  often have different sized noses. As a result, different sized nasal prongs will be better suited for a particular patient depending upon the size of the patient&#39;s nose. Patient interface device  2  is often provided, therefore, with multiple pillow sleeves  14  having differing size nasal prongs  22  so that the appropriate pillow sleeve  14  can be selected by the patient. However, changing pillow sleeves  14  requires complete disassembly of the nasal pillow assembly  6 , which can be time consuming and inconvenient.  FIG. 39  shows a pillow sleeve assembly  238  according to another embodiment of the invention which addresses this problem. The pillow sleeve assembly  238  includes a pillow sleeve  240  having openings  242  provided therein which are adapted to receive and hold removable nasal prongs  244  of various different sizes. Thus, a patient is able to select the proper size nasal prongs  244  without the need to completely disassemble a nasal pillow assembly that includes the pillow sleeve assembly  238 . 
         [0080]      FIG. 40  is an isometric view of a patient interface device  246  according to yet a further alternative embodiment of the invention. The patient interface device  246  includes a nasal pillow assembly  248  that includes a cushion portion  250  made of a flexible material such as, without limitation, silicone, having nasal prongs  252  extending therefrom. Cushion portion  250  is attached to rigid frame portion  254  by, for example, over molding the two pieces together, adhering the two pieces together using a suitable adhesive, or attaching the two pieces together using any suitable mechanical attachment mechanism. Support frame portion  254  is made of a suitable rigid material, such as, without limitation, plastic. Support frame portion  254  includes connector portions  256  structured to be attached to straps  258  of a headgear forming a part of the patient interface device  246 . Furthermore, the patient interface device  246  includes a tube assembly  260  that is connected to a source of pressurized gas. The tube assembly  260  includes a main conduit  262 , an elbow portion  264  and a connecting portion  266 . As shown by the arrows in  FIG. 40 , the main conduit  262  is structured to be able to rotate relative to the elbow portion  264 , the elbow portion  264  is structured to be able to independently rotate relative to the connecting portion  266 , and the tube assembly  260  in its entirety is structured to be slideable along the support frame portion  254  in order to selectively position the tube assembly  260  relative to the front of the nasal pillow assembly  248 . 
         [0081]      FIGS. 41 and 42  show one embodiment for implementing the sliding tube assembly  260  shown in  FIG. 40 . In particular, a sliding mount  268  is provided within the nasal pillow assembly  248  in sliding engagement with the support frame  254 . In addition, the sliding mount engages the support frame portion  254  in a manner which maintains an airtight seal. The sliding mount includes the connecting portion  266  in the form of a snap-on connector mount which is adapted to have snap fit thereon the elbow portion  264  in a manner which provides an airtight seal. In addition, a slideable sealing mechanism having a plurality of interconnected slide elements  272  is provided within an aperture  274  provided in the support frame  254  which enables the tube assembly  260  to be slid along the aperture  274  while at the same time maintaining an airtight seal and connection between the tube assembly  260  and the nasal pillow assembly  248 . The patient interface device  246 , by providing for multiple degrees of selective movement of the tube assembly  260 , including the ability to slide and selectively position the tube assembly along the front face of the nasal pillow assembly  248 , provides for added comfort and convenience for the patient. 
         [0082]    While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, deletions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as limited by the foregoing description but is only limited by the scope of the appended claims.