Abstract:
An elastic headgear that automatically adjusts to fit patients of different sizes and shape and that may be customized through selective placement of various accessories. The headgear includes a strap member having a central panel and a first arm member and a second arm extending from the central panel. The arm members each have at least one first attachment feature. The headgear also includes at least one accessory member having at least one second attachment feature, wherein the at least one second attachment feature is selectively mateable with the at least one first attachment feature to allow the at least one accessory member to be selectively attached to and positioned along either the first arm member or the second arm member at a plurality of different locations.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application claims the priority benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/650,511, filed on May 23, 2012, the contents of which are herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention pertains to patient interface devices structured to deliver a flow of breathing gas to a user, and, in particular, to a headgear for a patient interface device. 
         [0004]    2. Description of the Related Art 
         [0005]    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&#39;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&#39;s airway, and variable airway pressure, wherein the pressure provided to the airway of the patient is varied with the patient&#39;s respiratory cycle. Such therapies are typically provided to the patient at night while the patient is sleeping. 
         [0006]    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&#39;s nose, a nasal/oral mask that covers the patient&#39;s nose and mouth, or a full face mask that covers the patient&#39;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&#39;s head. 
         [0007]    In designing patient interface devices, particularly those for pressure support therapy for treating OSA, accurate fit to a given patient is a critical measure of therapy success. Poor fit to a given patient can result in excessive mask leak (reduced therapy pressures), mask over tightening, development of sore, abrasions and/or indentations on the patient&#39;s face. Specifically, poor fit of headgear impacts therapy success in that comfort and seal are compromised. 
       SUMMARY OF THE INVENTION 
       [0008]    Accordingly, it is an object of the present invention to provide a headgear for a patient interface device that overcomes the shortcomings of conventional headgear. This object is achieved according to the present invention by providing an elastic headgear that automatically adjusts to fit patients of different sizes and shape and that may be customized through selective placement of various accessories. 
         [0009]    In one embodiment, a headgear assembly for a patient interface device structured to deliver a flow of breathing gas to a patient is provided. The headgear assembly includes a strap member having a central panel and at least a first arm member extending from a first side of the central panel and a second arm member extending from a second side of the central panel opposite the first side, the central panel, the first arm member and the second arm member being made of an elastic non-textile material having at least one of a tensile modulus of 1.5 Mpa to 10 Mpa and an elongation without break of 400% to 1100%. In addition, the first arm member and the second arm member each have at least one first attachment feature. The headgear assembly also includes at least one accessory member having at least one second attachment feature, wherein the at least one second attachment feature is selectively mateable with the at least one first attachment feature to allow the at least one accessory member to be selectively attached to and positioned along either the first arm member or the second arm member at a plurality of different locations. 
         [0010]    In another embodiment, a headgear assembly for a patient interface device structured to deliver a flow of breathing gas to a patient is provided. The headgear assembly includes a strap member including: (i) a base member made of an elastic material having at least one of a tensile modulus of 1.5 Mpa to 10 Mpa and an elongation without break of 400% to 1100%, wherein the base member includes a central panel portion and at least a first base arm member extending from a first side of the central panel portion and a second base arm member extending from a second, opposite side of the central panel portion, wherein the first base arm member and the second base arm member each have at least one first attachment feature, (ii) a central reinforcing portion coupled to and covering only a portion of the central panel portion, (iii) a first arm reinforcing portion coupled to and covering only a portion of the first base arm member, and (iv) a second arm reinforcing portion coupled to and covering only a portion of the second base arm member. 
         [0011]    The central reinforcing portion, the first arm reinforcing portion and the second arm reinforcing portion are made of an inelastic material having at least one of a tensile modulus greater than or equal to 15 Mpa and an elongation without break of less than or equal to 60%. The headgear assembly also includes at least one accessory member having at least one second attachment feature ( 42 ,  76 ), wherein the at least one second attachment feature is selectively mateable with the at least one first attachment feature to allow the at least one accessory member to be selectively attached to and positioned along either the first base arm member or the second base arm member at a plurality of different locations. 
         [0012]    These and other objects, features, and characteristics of the present invention, 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. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a schematic diagram of a system adapted to provide a regimen of respiratory therapy to a patient according to one exemplary embodiment of the invention; 
           [0014]      FIG. 2  is a top plan view of a strap member forming a part of a patient interface device of the system of  FIG. 1  according to an exemplary embodiment of the present invention; 
           [0015]      FIGS. 3 and 4  are side elevational views of pad members that may be selectively coupled to the strap member of  FIG. 2 ; 
           [0016]      FIG. 5  is a side elevational view of a tube clip that may be selectively coupled to the strap member of  FIG. 2 ; 
           [0017]      FIG. 6  is a top plan view of a strap member according to an alternative exemplary embodiment; 
           [0018]      FIG. 7  is a schematic diagram of a system adapted to provide a regimen of respiratory therapy to a patient that employs the strap member of  FIG. 6 ; 
           [0019]      FIGS. 8 and 9  are schematic diagrams of systems adapted to provide a regimen of respiratory therapy to a patient according to alternative exemplary embodiments of the invention; 
           [0020]      FIG. 10  is a bottom plan view of a strap member according to another alternative exemplary embodiment; 
           [0021]      FIG. 12  is a side elevational view and  FIG. 13  is a cross-sectional view taken along lines B-B of  FIG. 11  of a pad members that may be selectively coupled to the strap member of  FIG. 10 ; 
           [0022]      FIG. 14  is a bottom plan view of a strap member according to still another alternative exemplary embodiment; 
           [0023]      FIG. 15  is a top plan view of a strap member according to yet another alternative exemplary embodiment; 
           [0024]      FIG. 16  is a top plan view of a base member forming a part of the strap member of  FIG. 15 ; 
           [0025]      FIG. 17  is a top plan view showing certain reinforcing members forming a part of the strap member of  FIG. 15 ; 
           [0026]      FIGS. 18 ,  19  and  20  are cross-sectional views taken along lines C-C, D-D, and E-E, respectively, of  FIG. 15 ; 
           [0027]      FIGS. 21 and 22  are schematic diagrams of systems adapted to provide a regimen of respiratory therapy to a patient that employ the strap member of  FIG. 15 ; 
           [0028]      FIGS. 23 ,  24  and  25  are top plan views of a strap member according to yet another alternative exemplary embodiment; 
           [0029]      FIG. 26  is a bottom plan view of a base member forming a part of the strap member of  FIG. 25 ; and 
           [0030]      FIG. 27  is a cross-sectional view taken along lines F-E of  FIG. 25 . 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0031]    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, “directly coupled” means that two elements are directly in contact with each other. 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. 
         [0032]    As used herein, the word “unitary” means a component is created as a single piece or unit. That is, a component that includes pieces that are created separately and then coupled together as a unit is not a “unitary” component or body. 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 employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality). 
         [0033]    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. 
         [0034]    A system  2  adapted to provide a regimen of respiratory therapy to a patient according to one exemplary embodiment of the invention is generally shown in  FIG. 1 . System  2  includes a pressure generating device  4 , a delivery conduit  6 , and a patient interface device  8  including an elbow conduit  10 . Pressure generating device  4  is 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 conduit  6  is structured to communicate the flow of breathing gas from pressure generating device  4  to patient interface device  8 . 
         [0035]    In the illustrated embodiment, patient interface device  8  comprises a nasal/oral mask structured to cover the nose and mouth of the patient. However, other types of patient interface devices  8 , such as, without limitation, a nasal mask that covers the patient&#39;s nose, or a full face mask that covers the patient&#39;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. 
         [0036]    In the embodiment shown in  FIG. 1 , patient interface device  8  includes a cushion assembly  12 , a faceplate member  14  (also called a shell), and a headgear assembly  16 . Cushion assembly  12  includes a cushion member  18  coupled to a support ring  20 . In the exemplary embodiment, cushion member  18  is 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. In addition, support ring  20  is 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 assembly  12  to faceplate member  14 . Faceplate member  14  is also made of a rigid or semi-rigid material, such as, without limitation, an injection molded thermoplastic or silicone. An opening in faceplate member  14  to which elbow conduit  10  is coupled allows the flow of breathing gas from pressure generating device  4  to be communicated to an interior space defined by faceplate member  14  and cushion assembly  12 , and then, to the airway of a patient. The opening in faceplate member  14  also allows the flow of exhalation gas (from the airway of such a patient) to be communicated to exhaust vent  22  provided in elbow conduit  10 . As described in greater detail below, headgear assembly  16  is structured to enable patient interface device to be secured to the head of the patient in a manner that creates a suitable seal with cushion assembly  12 . 
         [0037]    In the exemplary embodiment, headgear assembly  16  includes strap member  24  that is adjustably coupled to a back piece  26 . In addition, headgear assembly  16  further includes a number of pad members  28  (labeled  28 A,  28 B in the illustrated embodiment) that are able to be selectively coupled to strap member  24  at desired locations as described herein. Pad members  28  are each structured to provide one or more of a support, anti-slip and/or anti-red-mark (i.e., anti-pressure) functionality for patient interface device  8 . In addition, as described elsewhere herein, other types of accessories, such as, without limitation, a tube positioning/management clip, are also able to be selectively coupled to strap member  24  at desired locations. 
         [0038]      FIG. 2  is a top plan view of strap member  24  according to an exemplary embodiment of the present invention. Strap member  24  includes a central panel  30  and four arm members  32 A,  32 B,  32 C,  32 D, wherein arm members  32 A,  32 B extend from a first side of central panel  30  and arm members  32 C,  32 D extend from a second, opposite side of central panel  30 . Central panel  30  and arm members  32 A,  32 B,  32 C,  32 D are, in the exemplary embodiment, part of a unitary structure made of a highly elastic material that is not a textile (i.e., a non-textile material). As used herein, the word “textile” means a material consisting of a network of interlaced or otherwise entangled natural or artificial fibers made by, for example and without limitation, weaving, knitting, spreading, crocheting, or bonding (e.g., by chemical, mechanical, heat or solvent treatment) the fibers to form the network, and may include, for example, and without limitation, woven and nonwoven fabric materials. In the exemplary embodiment, the highly elastic material of central panel  30  and arm members  32 A,  32 B,  32 C,  32 D has a tensile modulus of 1.5 Mpa to 10 Mpa and/or an elongation (without break) of 400% to 1100% (alternatively, 600% to 1100%), and may be, for example and without limitation, a low durometer elastomer (e.g., without limitation, natural rubber, neoprene, neoprene, silicone, or polyurethane). 
         [0039]    In one particular embodiment, for low pressure (5 to 10 cmH 2 O) applications (e.g., employing nasal pillows or nasal mask type interfaces), the highly elastic material of central panel  30  and arm members  32 A,  32 B,  32 C,  32 D has a tensile modulus of 3 Mpa to 5 Mpa and/or an elongation (without break) of 800% to 1000%. In another particular embodiment, for mid-high pressure (10 to 20 cmH 2 O) applications, the highly elastic material of central panel  30  and arm members  32 A,  32 B,  32 C,  32 D has a tensile modulus of 5 Mpa to 9 Mpa and/or an elongation (without break) of 400% to 600%. In addition, in the exemplary embodiment, central panel  30  and arm members  32 A,  32 B,  32 C,  32 D each have a thickness of 1.5 mm to 5 mm. 
         [0040]    As seen in  FIG. 2 , central panel  30  includes a central orifice  34 , the purpose of which is described elsewhere herein. In addition, each arm member  32 A,  32 B,  32 C,  32 D includes a series of attachment orifices  36  (labeled  36 A,  36 B,  36 C,  36 D) that are spaced along a portion of the length of arm member  32 A,  32 B,  32 C,  32 D. In the exemplary embodiment, attachment orifices  36  are spaced evenly the portion of the length of arm member  32 A,  32 B,  32 C,  32 D (e.g., one every 1 cm along an arm having a length of 25 cm to 38 cm). 
         [0041]    Attachment orifices  36  are provided to enable one or more suitably structured accessory elements, such as a pad member  28 , to be selectively attached to any of arm members  32 A,  32 B,  32 C,  32 D at a desired location. In particular,  FIG. 3  is a side elevational view of pad member  28 A according to one non-limiting, exemplary embodiment. Pad member  28 A includes a contact layer  38 A coupled to a base/backing layer  40 A. Contact layer  38 A is structured to engage the face of the user of patient interface device  8 , and may be made of a suitable, cushiony material such as, without limitation, a polyurethane based gel, a silicone based gel, or foam. In one specific embodiment, the material of contact layer  38  is tacky (at least at the outer surface) so as to prevent pad member  28 A, and thus the rest of patient interface device  8  coupled to pad member  28 A, from moving relative to the face of the user, thereby reducing the likelihood of abrasions being created. Base/backing layer  40 A is made of a material that is of a higher durometer than contact layer  38 A. Such material may include, without limitation, a thermoplastic material or a textile, such as a woven fabric material. 
         [0042]    A number of button elements  42 A (e.g., three) are provided on the surface of base/backing layer  40 A opposite contact layer  38 A. The spacing between each button element along base/backing layer  40 A is the same as the spacing of attachment orifices  36  of arm members  32 . Each button element  42 A includes a post member  44 A and an enlarged cap member  46 A attached to post member  44 A. Button element  42 A may be made from any of a number of suitable materials, such as, without limitation, plastic (e.g., the same thermoplastic as base/backing layer  40 A) or metal. Thus, pad member  28 A is able to be selectively attached to any of the arm members  32 A,  32 B,  32 C,  32 D by inserting the button elements  42 A through selected, appropriately spaced attachment orifices  36 . 
         [0043]    As will be appreciated, the elastic nature of arm members  32 A,  32 B,  32 C,  32 D will allow attachment orifices  36  to temporarily stretch to receive cap members  46 A and then return to their original size around post members  44 A. As will also be appreciated, any number of pad members  28 A may be attached to any number of arm members  32 A,  32 B,  32 C,  32 D in this manner as desired. In addition,  FIG. 4  is a side elevational view of pad member  28 B according to another exemplary embodiment. Pad member  28 B is similar to pad member  28 A (like components are labeled with like reference numerals having a “B” designation rather than an “A” designation), except that it has a generally circular profile and is smaller than pad member  28 A. Thus, pad member  28 B is able to be selectively attached to any of the arm members  32 A,  32 B,  32 C,  32 D by inserting the button element  42 B through a selected attachment orifice  36 . 
         [0044]      FIG. 5  is a side elevational view of an accessory in the form of a tube positioning/management clip  48  according to a further exemplary embodiment. Tube positioning/management clip  48  includes a looped holding portion  50  structured to receive and hold delivery conduit  6 , and a button element  42  as described elsewhere herein. Thus, tube positioning/management clip  48  is able to be selectively attached to any of the arm members  32 A,  32 B,  32 C,  32 D by inserting the button element  42  through a selected attachment orifice  36  to enable the delivery conduit  6  to be held thereby in a desired position/location so as to no bother the user during therapy. 
         [0045]    Referring again to  FIG. 2 , in the illustrated embodiment, the distal end of each of the arm members  32 A,  32 B,  32 C,  32 D is provided with a hook and loop fastening system (e.g., Velcro®) on the top surface thereof that comprises a hook portion  52 A,  52 B,  52 C,  52 D spaced from a loop portion  54 A,  54 B,  54 C,  54 D. These hook and loop fastening systems enable strap member  24  (having one or more accessories coupled thereto as described herein) to be adjustably coupled to back piece  26  by inserting each distal end of each arm member  32 A,  32 B,  32 C,  32 D through a respective looped connector  56  ( FIG. 1 ) provided on back piece  26  and then bending the distal end back on itself at a desire location to secure the hook portion  52  to the loop portion  54 . The hook and loop fastening system as just described is not meant to be limiting, and it will be understood that other types of fastening systems are also contemplated within the scope of the present invention. 
         [0046]    Thus, in order to don patient interface device  8 , the user will typically first position cushion assembly  12  within the rear of central panel  30  of strap member  24  (having one or more accessories coupled thereto as described herein) in a manner wherein a portion of faceplate member  14  and elbow conduit  10  are inserted through central orifice  34  as seen in  FIG. 1 . The user will then place headgear assembly  16  onto his or her head and adjust each arm member  32 A,  32 B,  32 C,  32 D as just described until an appropriate fit and seal are achieved. 
         [0047]    In an alternative embodiment, rather than the distal end of each arm member  32 A,  32 B,  32 C,  32 D being provided with a hook and loop fastening system as just described, arm member  32 A may be attached to arm member  32 C and arm member  32 B may be attached to arm member  32 D as shown in  FIG. 6  (which is a top plan view of an alternative strap member  24 ′ showing alternative arm members  32 A′,  32 B′,  32 C′,  32 D′ thus configured). In such an implementation, patient interface device  8 ′ forming a part of an alternative system  2 ′, shown in  FIG. 7 , may be donned by simply placing arm members  32 A′,  32 B′,  32 C′,  32 D′ over the user&#39;s head. Adjustment in this embodiment is provided automatically by the elastic properties of alternative strap member  24 ′, which may be made of the same materials that were described in connection with strap member  24 . 
         [0048]    Moreover, according to a further aspect of the invention, strap member  24  and alternative strap member  24 ′ are reversible as shown in  FIGS. 8 and 9 , respectively, wherein they are used to implement further alternative systems  2 ″ (FIG.  8 ) and  2 ′″ ( FIG. 9 ) employing alternative patient interface devices  8 ″ and  8 ′″. By reversible, it is meant that central panel  30  and central panel  30 ′, rather than being used as a holder and stabilizer for cushion assembly  12  as seen in  FIGS. 1 and 7 , are instead deployed at the back of the user&#39;s head as a stabilizer and, for example, a pony tail holder. In addition, in the embodiments of  FIGS. 8 and 9 , alternative cushion assemblies  12 ″ and  12 ′″ are employed that each have a frame member having a faceplate portion and a forehead support portion. 
         [0049]      FIG. 10  is a bottom plan view of a strap member  60  according to another, alternative exemplary embodiment of the present invention that may be used in place of strap member  24 . Strap member  60  includes a central panel  62  and four arm members  64 A,  64 B,  64 C,  64 D, wherein arm members  64 A,  64 B extend from a first side of central panel  62  and arm members  64 C,  64 D extend from a second, opposite side of central panel  62 . Central panel  62  and arm members  64 A,  64 B,  64 C,  64 D are, in the exemplary embodiment, part of a unitary structure made of a highly elastic material that is not a textile (i.e., a non-textile material). In the exemplary embodiment, the highly elastic material of central panel  62  and the portion of arm members  64 A,  64 B,  64 C,  64 D not forming channels  68  has a tensile modulus of 1.5 Mpa to 10 Mpa and/or an elongation (without break) of 400% to 1100% (alternatively, 600% to 1100%), and may be, for example and without limitation, a low durometer elastomer (e.g., without limitation, natural rubber, neoprene, silicone, or polyurethane). 
         [0050]    In one particular embodiment, for low pressure (5 to 10 cmH 2 O) applications (e.g., employing nasal pillows or nasal mask type interfaces), the highly elastic material of central panel  62  and the portion of arm members  64 A,  64 B,  64 C,  64 D not forming channels  68  has a tensile modulus of 3 Mpa to 5 Mpa and/or an elongation (without break) of 800% to 1000%. In another particular embodiment, for mid-high pressure (10 to 20 cmH 2 O) applications, the highly elastic material of central panel  62  and the portion of arm members  64 A,  64 B,  64 C,  64 D not forming channels  68  has a tensile modulus of 5 Mpa to 9 Mpa and/or an elongation (without break) of 400% to 600%. Furthermore, the portion of arm members  64 A,  64 B,  64 C,  64 D forming channels  68  (i.e., the wall portion within 5-8 mm, or approximately ⅓ of overall strap width, of the void of the channels  68 ) has a higher tensile modulus of 8 Mpa to 10 Mpa and a lower elongation (without break) of less than or equal to 650%. As will be appreciated, these portions of differing tensile modulus may be made using a two step molding process. In addition, in the exemplary embodiment, central panel  62  and the portion of arm members  64 A,  64 B,  64 C,  64 D not forming channels  68  each have a thickness of 1.5 mm to 3 mm, and the portion of arm members  64 A,  64 B,  64 C,  64 D forming channels  68  have a thickness of 2.5 mm to 5 mm. 
         [0051]    As seen in  FIG. 10 , central panel  62  includes a central orifice  66 . In addition, each arm member  64 A,  64 B,  64 C,  64 D includes an attachment channel  68  (labeled  68 A,  68 B,  68 C,  68 D) provided in the bottom surface thereof that extends along a portion of the length thereof.  FIG. 11  is a cross-sectional view taken along lines A-A of  FIG. 10  which shows attachment channel  68 A. As will be appreciated, attachment channels  68 B,  68 C, and  68 D will have a similar structure. In addition, the top surface of the distal end of each arm member  64 A,  64 B,  64 C,  64 D includes a hook and loop fastening system (not shown) to enable it to be coupled to adjustably coupled to the head of the user as described elsewhere herein. 
         [0052]    Attachment channels  68  are provided to enable one or more suitably structured accessory elements, such as a pad member  70  shown in  FIGS. 12 and 13 , to be selectively attached to any of arm members  64 A,  64 B,  64 C,  64 D.  FIG. 12  is a side elevational view of pad member  70  and  FIG. 13  is a cross-sectional view of pad member  70  taken along lines B-B of  FIG. 12  according to one exemplary embodiment. Pad member  70  includes a contact layer  72  coupled to a base/backing layer  74 , which are similar in structure, function and material to contact layer  38 A base/backing layer  40 A described elsewhere herein. In addition, a mating pin member  76  is provided on the surface of base/backing layer  74  opposite contact layer  72 . Mating pin member  76  is sized to be securely received and held within any of the flexible attachment channels  68 B,  68 C, and  68 D. 
         [0053]    In the exemplary embodiment, the attachment channels  68  are longer than the mating pin member  76 . Thus, pad member  70  is able to be selectively attached to any of the arm members  64 A,  64 B,  64 C,  64 D at a desired location by inserting mating pin member  76  into an attachment channel at the desired location. As will be appreciated, the elastic nature of arm members  64 A,  64 B,  64 C,  64 D will allow attachment channels  68  to temporarily expand to receive mating pin member  76  and then retract to hold mating pin member  76 . As will also be appreciated, any number of pad members  70  (or alternative accessories (e.g., a circular pad member or a tube position/management clip) having a suitable mating pin member) may be attached to any number of arm members  64 A,  64 B,  64 C,  64 D in this manner as desired. 
         [0054]    In an alternative embodiment, rather than the distal end of each arm member  64 A,  64 B,  64 C,  64 D being provided with a hook and loop fastening system as just described, arm member  64 A may be attached to arm member  64 C and arm member  64 B may be attached to arm member  64 D as shown in  FIG. 14  (which is a bottom plan view of an alternative strap member  60 ′ showing alternative arm members  64 A′,  64 B′,  64 C′,  64 D′ thus configured). In such an implementation, a patient interface device employing strap member  60 ′ may be donned by simply placing arm members  64 A′,  64 B′,  64 C′,  64 D′ over the user&#39;s head. Adjustment in this embodiment is provided automatically by the elastic properties of alternative strap member  60 ′. Furthermore, according to a further aspect of the invention, strap member  60  and alternative strap member  60 ′ are reversible as described elsewhere herein. 
         [0055]      FIG. 15  is a top plan view of a strap member  80  according to still another, alternative exemplary embodiment of the present invention that may be used in place of strap member  24 . Strap member  80  includes a central panel  82  and four arm members  84 A,  84 B,  84 C,  84 D, wherein arm members  84 A,  84 B extend from a first side of central panel  82  and arm members  84 C,  84 D extend from a second, opposite side of central panel  82 . 
         [0056]    Strap member  80  is of the present embodiment is formed as a reinforced composite structure. More specifically, strap member  80  comprises a base member  86 , shown in top plan view in  FIG. 16 , having a central panel portion  88  defining an orifice  90 , and arm members  92 A,  92 B,  92 C,  92 D having orifices  94 . In the exemplary embodiment, base member  86  is a unitary structure made of a highly elastic material. In the exemplary embodiment, the highly elastic material of base member  86  has a tensile modulus of 1.5 Mpa to 10 Mpa and/or an elongation (without break) of 400% to 1100% (alternatively, 400% to 1100%), and may be, for example and without limitation, a low durometer elastomer, or a flexible, elastic textile. In one embodiment, if a flexible textile is employed, the weave thereof should be such that it will stretch only along the longitudinal axes of the arm members  92 A,  92 B,  92 C,  92 D. 
         [0057]    In one particular embodiment, for low pressure (5 to 10 cmH 2 O) applications (e.g., employing nasal pillows or nasal mask type interfaces), the highly elastic material of base member  86  has a tensile modulus of 3 Mpa to 5 Mpa and/or an elongation (without break) of 800% to 1000%. In another particular embodiment, for mid-high pressure (10 to 20 cmH 2 O) applications, the highly elastic material of base member  86  has a tensile modulus of 5 Mpa to 9 Mpa and/or an elongation (without break) of 400% to 600%. In addition, in the exemplary embodiment, base member  86  has a thickness of 1.5 mm to 3 mm. 
         [0058]    In addition, strap member  80  also includes a plurality of reinforcing portions that are provided on top of and attached to base member  86 . In particular, as seen in  FIG. 17 , such reinforcing portions include a central reinforcing portion  96  having a central orifice  98 , and arm reinforcing portions  100 A,  100 B,  100 C,  100 D having orifices  102 . The distal ends of arm reinforcing portions  100 A,  100 B,  100 C,  100 D are provided with a hook and loop fastening system comprising a hook portion  104  and a loop portion  106  as described elsewhere herein. In the exemplary embodiment, central reinforcing portion  96  and arm reinforcing portions  100 A,  100 B,  100 C,  100 D are made of an inelastic material having a tensile modulus greater than or equal to 15 Mpa and/or an elongation (without break) of less than or equal to 60%, and may include a textile material, such as a woven fabric, or a thermoplastic material. Also, the thickness of each of central reinforcing portion  96  and arm reinforcing portions  100 A,  100 B,  100 C,  100 D may be 0.2 mm to 1.5 mm and could be layered as necessary to create a structure up to 5 to 6 mm thick in total. 
         [0059]    Thus, when formed, as seen in  FIG. 15 , strap member  80  will include certain reinforced portions (having both the elastic and inelastic materials) and certain non-reinforced portions (having only the elastic material). In particular, central panel  82  has a central non-reinforced portion  108  surrounded by an outer reinforced portion  110 . These sections are shown in  FIG. 18 , which is a cross-sectional view of strap member  80  taken along lines C-C in  FIG. 15 . Also, each arm member  84  has an inner, proximal non-reinforced portion  112  located immediately adjacent central panel  82 , and an outer, distal reinforced portion  114  spaced from central panel  82  by non-reinforced portion  112 . These sections are shown in  FIGS. 19 and 20 , which are cross-sectional views of strap member  80  taken along lines D-D and E-E, respectively, in  FIG. 15 . 
         [0060]    Strap member  80  may thus be used to implement a system  116  and a system  118 , shown in  FIGS. 21 and 22 , respectively, which are similar to system  2  of  FIG. 1  and system  2 ″ of  FIG. 8  (like components are labeled with like reference numerals). 
         [0061]    In an alternative embodiment, rather than the distal end of each arm member  84 A,  84 B,  84 C,  84 D being provided with a hook and loop fastening system as described above, arm member  84 A may be attached to arm member  84 C and arm member  84 B may be attached to arm member  84 D as shown in  FIG. 23  (which is a top plan view of an alternative strap member  80 ′ showing alternative arm members  84 A′,  84 B′,  84 C′,  84 D′ thus configured; other similar components are denoted by like reference numerals followed by a “′” symbol). In such an implementation, a patient interface device employing strap member  80 ′ may be donned in system  2 ′ or system  2 ′″ in place of strap member  24 ′ by simply placing arm members  84 A′,  84 B′,  84 C′,  84 D′ over the user&#39;s head. Adjustment in this embodiment is provided automatically by the elastic properties of non-reinforced portions  112 A′ through  112 D′. 
         [0062]      FIG. 24  is a top plan view of another alternative strap member  80 ″ showing alternative arm members  84 A″,  84 B″,  84 C″,  84 D″, wherein arm member  84 A″ is attached to arm member  84 C″ and arm member  84 B″ may is attached to arm member  84 D″ (other similar components are denoted by like reference numerals followed by a “″” symbol). As seen in  FIG. 24 , strap member  80 ″ includes an additional non-reinforced section  120 A at the point where arm member  84 A″ is attached to arm member  84 C″ and an additional non-reinforced section  120 B at the point where arm member  84 B″ is attached to arm member  84 D″. In such an implementation, a patient interface device employing strap member  80 ″ may be donned in system  2 ′ or system  2 ′ in place of strap member  24 ′, wherein additional non-reinforced sections  120 A and  120 B will provide additional elastic sections to facilitate self-adjustment. 
         [0063]      FIG. 25  is a top plan view of a strap member  122  according to still another, alternative exemplary embodiment of the present invention. Strap member  122  is similar to strap member  80  in that it includes a central panel  124  and four arm members  126 A,  126 B,  126 C,  126 D. In addition, strap member  122  is formed as a reinforced composite structure. Strap member  122  thus includes a base member  128 , shown in bottom plan view in  FIG. 26 , having a central panel portion  130  defining an orifice  132 , and arm members  134 A,  134 B,  134 C,  134 D. Arm members  134 A,  134 B,  134 C,  134 D each include an attachment channel  136  that is similar to attachment channels  68  ( FIG. 10 ). In the exemplary embodiment, base member  128  is a unitary structure made of a highly elastic material. In the exemplary embodiment, the highly elastic material in the portion of base member  128  not forming channels  136  has a tensile modulus of 1.5 Mpa to 10 Mpa and/or an elongation (without break) of 400% to 1100% (alternatively, 400% to 1100%), and may be, for example and without limitation, a low durometer elastomer (e.g., without limitation, natural rubber, neoprene, silicone, or polyurethane), or a flexible, elastic textile. In one particular embodiment, for low pressure (5 to 10 cmH 2 O) applications (e.g., employing nasal pillows or nasal mask type interfaces), the highly elastic material of base member  128  not forming channels  136  has a tensile modulus of 3 Mpa to 5 Mpa and/or an elongation (without break) of 800% to 1000%. 
         [0064]    In another particular embodiment, for mid-high pressure (10 to 20 cmH 2 O) applications, the highly elastic material of base member  128  not forming channels  136  has a tensile modulus of 5 Mpa to 9 Mpa and/or an elongation (without break) of 400% to 600%. Furthermore, the portion of base member  128  forming channels  136  (i.e., the wall portion within 5-8 mm, or approximately ⅓ of overall strap width, of the void of the channels  136 ) has a higher tensile modulus of 8 Mpa to 10 Mpa and a lower elongation (without break) of less than or equal to 650%. As will be appreciated, these portions of differing tensile modulus may be made using a two step molding process. In addition, in the exemplary embodiment, base member  128  has a thickness of 1.5 mm to 3 mm. 
         [0065]    Strap member  122  is formed by attaching a plurality of reinforcing portions to the top of base member  126 . In particular, as seen in  FIG. 25 , a central reinforcing portion  138  having a central orifice  140 , and arm reinforcing portions  142 A,  142 B,  142 C,  142 D are attached to the top of base member  126 . 
         [0066]    Thus, when formed, as seen in  FIG. 25 , strap member  122  will include certain reinforced portions (having both the elastic and inelastic materials) and certain non-reinforced portions (having only the elastic material). In particular, central panel  124  has a central non-reinforced portion  144  surrounded by an outer reinforced portion  146 . Also, each arm member  126  has an inner, proximal non-reinforced portion  148  located immediately adjacent central panel  124 , and an outer, distal reinforced portion  150  spaced from central panel  124  by non-reinforced portion  148 . 
         [0067]    In addition, the provision of attachment channels  136  allows suitably structured accessories (e.g., pad  70  with mating pin member  76 ) to be selectively attached to arm members  126 A,  126 B,  126 C,  126 D in the manner described elsewhere herein. This is illustrated in  FIG. 27 , which includes a cross-section of arm member  126 C taken along lines F-F in  FIG. 25 . 
         [0068]    In another alternative embodiment, rather than the distal end of each arm member  126 A,  126 B,  126 C,  126 D being provided with a hook and loop fastening system as described above, arm member  126 A may be attached to arm member  126 C and arm member  126 B may be attached to arm member  126 D in a manner similar to that shown in  FIGS. 23 and 24  and described herein. 
         [0069]    In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word “comprising” or “including” does not exclude the presence of elements or steps other than those listed in a claim. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. In any device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain elements are recited in mutually different dependent claims does not indicate that these elements cannot be used in combination. 
         [0070]    Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.