Patent Publication Number: US-2013247915-A1

Title: Patient interface device with multi-axis elbow conduit

Description:
This patent application claims the priority benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/418,903 filed on Dec. 2, 2010, the contents of which are herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to respiratory patient interface devices, and, in particular, to a respiratory patient interface device having an elbow conduit that provides for movement in multiple axes. 
     2. Description of the Related Art 
     There are numerous situations where it is necessary or desirable to deliver a flow of breathing gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube in their 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 obstructive sleep apnea (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. 
     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 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 cushion having nasal prongs that are received within the patient&#39;s nares, a nasal/oral mask that covers the 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 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. 
     Patients that must utilize the respiratory therapies as just described are often confronted with the problem of managing the tubing that extends between the ventilator or pressure support device and the patient interface device and carries the flow of gas from the ventilator or pressure support device to the patient interface device. In particular, they frequently struggle with tubing torque on the patient interface device as body movement occurs while asleep. Such tubing torque can negatively impact mask stability and result in a loss of the seal of the mask on the face of the patient. These issues often frustrate the patient and can interfere with the effective delivery of therapy. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a patient interface device that overcomes the shortcomings of conventional patient interface device. This object is achieved according to one embodiment of the present invention by providing a patient interface device that includes a frame, a cushion coupled to the frame, and a fluid coupling conduit having a first conduit member and a second conduit member. The first conduit member is fluidly coupled to at least one of the frame and the cushion and rotatable with respect to the frame and about a longitudinal axis of the first conduit member. The second conduit member is fluidly coupled to first conduit member and is rotatable with respect to the first conduit member and about an axis that is transverse to the longitudinal axis of the first conduit member. 
     In another embodiment, a fluid coupling conduit for a patient interface device is provided that includes a first conduit member structured to be fluidly coupled to at least one of a frame and a cushion of the patient interface device and being rotatable with respect to the frame and about a longitudinal axis of the first conduit member when coupled to the frame, and a second conduit member, the second conduit member being fluidly coupled to first conduit member and being rotatable with respect to the first conduit member and about an axis that is transverse to the longitudinal axis of the first conduit member. 
     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  
         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 present invention; 
         FIG. 2  is a side isometric view of an elbow conduit of a patient interface device forming a part of the system of  FIG. 1  according to an exemplary embodiment of the invention; 
         FIG. 3  is a rear elevational view of the elbow conduit of  FIG. 2 ; 
         FIG. 4  is a bottom isometric view of a first conduit member of the elbow conduit of  FIGS. 2 and 3 ; 
         FIG. 5  is a side isometric view of the first conduit member of  FIG. 4 ; 
         FIG. 6  is a bottom isometric view of a second conduit member of the elbow conduit of  FIGS. 2 and 3 ; 
         FIG. 7  is a side isometric view of the second conduit member of  FIG. 6 ; 
         FIG. 8  is an isometric view of an elbow conduit having a split ring washer attached thereto according to an alternative exemplary embodiment of the invention; 
         FIG. 9  is a top plan view of the split ring washer shown in  FIG. 8  for securing the elbow conduit of  FIG. 8  to a frame or faceplate of a patient interface device; 
         FIG. 10  is an isometric view of a swivel connector assembly forming part of the elbow conduit of  FIG. 8 ; 
         FIGS. 11 and 12  are isometric views of first and second members, respectively, of the swivel connector assembly of  FIG. 10 ; 
         FIG. 13  is a side elevational view of a pivot assembly forming part of the elbow conduit of  FIG. 8 ; 
         FIG. 14  is a front elevational view of the pivot assembly of  FIG. 13 ; 
         FIGS. 15-17  are a front isometric view, a front elevational view, and a bottom isometric view, respectively, of a first conduit member of the pivot assembly of  FIGS. 13 and 14 ; 
         FIGS. 18 and 19  are a side elevational view and a front isometric view, respectively, of a second conduit member of the pivot assembly of  FIGS. 13 and 14 ; 
         FIGS. 20 and 21  are side and isometric views of an elbow conduit according to another alternative exemplary embodiment of the invention; 
         FIG. 22  is an isometric view of a first conduit member of the elbow conduit of  FIGS. 20 and 21 ; and 
         FIG. 23  is an isometric view of a second conduit member of the elbow conduit of  FIGS. 20 and 21 . 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     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. 
     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). 
     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. 
     A system  2  adapted to provide a regimen of respiratory therapy to a patient according to one exemplary embodiment is generally shown in  FIG. 1 . System  2  includes a pressure generating device  4 , a patient circuit  6 , a patient interface device  8 , and an elbow conduit  10  according to one exemplary embodiment of the present invention which is described in greater detail herein. 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. Patient circuit  6  is structured to communicate the flow of breathing gas from pressure generating device  4  to patient interface device  8 , and typically includes a gas delivery conduit or tube coupled to elbow conduit  10 . 
     In the illustrated embodiment, patient interface  8  is a nasal mask structured to be placed over the nose of a patient. However, the present invention contemplates that the patient interface device can be any device suited to communicate a flow of gas with an airway of patient, such as a nasal cushion having nasal prongs that are received within the patient&#39;s nares, a nasal/oral mask that covers the nose and mouth, or a full face mask that covers the patient&#39;s face. That is any device that facilitates the delivery of the flow of breathing gas to, and the removal of a flow of exhalation gas from, the airway of such a patient may be used as patient interface  8  while remaining within the scope of the present invention 
     In the embodiment shown in  FIG. 1 , patient interface  8  includes a cushion  12  that is coupled to a rigid or semi-rigid frame or faceplate  14 . In the exemplary embodiment, frame  14  includes arms  16 A and  16 B each having a respective loop member  18 A,  18 B for receiving a respective strap  20 A,  20 B of a headgear component to secure patient interface device  8  to the patient&#39;s head. An opening in frame  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 cushion  12 , and then, to the airway of a patient. The opening in frame  14  also allows the flow of exhalation gas (from the airway of such a patient) to be communicated to an exhaust port  22  of elbow conduit  10  in the current embodiment. It will be appreciated that exhaust port need not be provided as part of elbow conduit  10 , but rather may be provided in a portion of patient interface device  8 , such as part of frame  14 . 
       FIG. 2  is a side isometric view and  FIG. 3  is a rear elevational view of elbow conduit  10  according to an exemplary embodiment of the invention. As described above, elbow conduit  10  is structured to be coupled to patient interface device  8  by being inserted into or otherwise coupled to an opening provided in frame  14 , and is also structured to be coupled to patient circuit  6 , which is a flexible tube or conduit, so that a breathing gas can be delivered from pressure generating device  4  to patient interface device  8 . In addition, as described in greater detail herein, elbow conduit  10  is structured to provide for simultaneous rotation in multiple axes with respect to frame  14 . 
     Elbow conduit  10  includes a first conduit member  24  and a second conduit member  26  that are rotatably coupled to one another as described herein. As seen in  FIG. 1 , first conduit member  24  is the part of elbow conduit  10  that provides the coupling to frame  14 , and second conduit member  26  is the part of elbow conduit  10  that provides the coupling to patient circuit  6 . 
       FIG. 4  is a bottom isometric view and  FIG. 5  is a side isometric view of first conduit member  24 . First conduit member  24  includes cylindrical connector portion  28  defining a first fluid chamber  30 . Cylindrical connector portion  28  is provided with U-shaped cut-out portions  32 , the function of which is described elsewhere herein. A bottom lip  34  is provided at the bottom of cylindrical connector portion  28 , and a top lip  36  is provided at the top of cylindrical connector portion  28 . A semi-cylindrical mating portion  38  is coupled to cylindrical connector portion  28  and defines a second fluid chamber  40  ( FIG. 5 ) that is fluidly coupled to first fluid chamber  30 . Semi-cylindrical mating portion  38  includes an arced surface  42  connected to a flat surface  44 . A port member  46  extends from flat surface  44  and provides fluid access to second fluid chamber  40 . In the exemplary embodiment, a plurality of apertures  48  are provided on arced surface for forming exhaust port  22  described elsewhere herein. First conduit member  24  thus defines a fluid path that extends from cylindrical connector portion  28  to semi-cylindrical mating portion  38  to port member  46 . 
       FIG. 6  is a bottom isometric view and  FIG. 7  is a side isometric view of second conduit member  26 . Second conduit member  26  includes cylindrical connector portion  50  defining first fluid chamber  52 . A bottom lip  54  is provided at the bottom of cylindrical connector portion  50 , and a top lip  56  is provided at the top of cylindrical connector portion  50 . A semi-cylindrical mating portion  58  is coupled to cylindrical connector portion  50  and defines a second fluid chamber  50  ( FIG. 7 ) that is fluidly coupled to first fluid chamber  52 . Semi-cylindrical mating portion  58  includes an arced surface  62  connected to a flat surface  64 . An orifice  66  is provided in flat surface  64  and provides fluid access to second fluid chamber  60 . Second conduit member  26  thus defines a fluid path that extends from cylindrical connector portion  50  to semi-cylindrical mating portion  58  to orifice  66 . In one particular, non-limiting exemplary embodiment, second conduit member  26  may further include an entrainment valve. 
     Elbow conduit  10  is assembled by inserting port member  46  of first conduit member  24  into orifice  66  of second conduit member  26 . When this is done, flat surfaces  44 ,  64  will engage one another ( FIG. 2 ), and second conduit member  26  will, in the exemplary embodiment, be able to rotate relative to first conduit member  24  over at least 180 degrees ( FIG. 3 ). More specifically, second conduit member  26  will be able to rotate about longitudinal axes through port member  46  and orifice  66 , which longitudinal axes are perpendicular to the longitudinal axis of both cylindrical connector portion  28  and cylindrical connector portion  50 . In alternative exemplary embodiments, second conduit member  26  will be able to rotate relative to first conduit member  24  over less than 180 degrees, over 10-180 degrees, over 20-180 degrees or over 0-200 degrees. 
     Alternatively, port member  46  may be replaced by an orifice and orifice  66  may be replaced by a port member such that the port member of second conduit member  26  is inserted into the orifice of first conduit member  24  during assembly. In either exemplary embodiment, the port member is held within the orifice by a snap fit. In one particular exemplary embodiment, the port member may be provided with slots (similar to U-shaped cut-out portions  32  described below) to facilitate the snap fit insertion into the orifice. 
     Once assembled as just described, cylindrical connector portion  28  of first conduit member  24  may be inserted into the opening in frame  14 . In the exemplary embodiment, U-shaped cut-out portions  32  allow cylindrical connector portion  28  to be temporarily compressed and reduced in diameter so that it can be inserted into the opening in frame  14  where it can snap in place after the compression force in removed. Once so connected, elbow conduit  10  is free to rotate within frame  14  about the longitudinal axis of first conduit member  24 . In addition, after elbow conduit  10  is connected to frame  14  as just described, the delivery conduit or tube of patient circuit  6  can be connected to cylindrical connector portion  50  of second conduit member  26 . In the exemplary embodiment, cylindrical connector portion  50  is sized to fit either a standard  15  mm hose or a standard 22 mm hose. In addition, a swivel connector may or may not be used for this connection. 
     Thus, when fully assembled as shown in  FIG. 1 , elbow conduit  10 , and, thus, the delivery conduit or tube of patient circuit  6  coupled thereto, is able to rotate 360 degrees about the longitudinal axis of first conduit member  24 . In addition, second conduit member  26 , and thus the delivery conduit or tube of patient circuit  6  coupled thereto, is able to simultaneously rotate at least 180 degrees about an axis that is perpendicular to the longitudinal axis of first conduit member  24 . This simultaneous, multi-axis rotation capability facilitates the movement of the tubing of patient circuit  6 , and as a result will reduce the adverse effects of tubing torque, resulting in increased mask stability and a decreased likelihood of seal loss. 
       FIG. 8  is an isometric view of an elbow conduit  70  according to an alternative exemplary embodiment of the invention. Elbow conduit  70  may be coupled to patient interface device  8  by being inserted into an opening provided in frame  14  (or an alternative patient interface device by being inserted into an opening provided in the frame or faceplate thereof), and may coupled to a gas delivery conduit or tube of patient circuit  6  so that a breathing gas can be delivered from pressure generating device  4  to patient interface device  8 . In addition, as described in greater detail herein, elbow conduit  70 , like elbow conduit  10 , is structured to provide for simultaneous rotation in multiple axes with respect to frame  14 . Elbow conduit  70  includes a pivot assembly  72  and a swivel connector assembly  76 , each of which is described in greater detail herein. In addition, as also described in greater detail herein, a split ring washer  74  is provided to secure elbow conduit  70  to frame  14 .  FIG. 9  is a top plan view of split ring washer  74 . 
       FIG. 10  is an isometric view of swivel connector assembly  76 . As seen in  FIG. 10 , swivel connector assembly  76  includes a first member  86  and a second member  88  rotatably coupled to one another.  FIG. 11  is an isometric view of first member  86 . First member  86  includes a cylindrical body portion  90  that is structured to be coupled to pivot assembly  72 , and a flat, circular engagement surface  92  located at one end cylindrical body portion  90 .  FIG. 12  is an isometric view of second member  88 . Second member  88  includes a first cylindrical body portion  94  structured to be received within first member  86  in a manner that allows for relative rotation between the two components, and a larger diameter second cylindrical body portion  96  provided adjacent first cylindrical body portion  94 . In addition, a plurality of individual, arc-shaped engagement structures  98  are provided along and spaced apart from one another about an outer peripheral portion of the end second cylindrical body portion  96  closest to first cylindrical body portion  94 . 
     Swivel connector assembly  76  is assembled by inserting first cylindrical body portion  94  into first member  86 . When this is done, engagement structures  98  will engage engagement surface  92  create a plurality of point-contacts between first member  86  and second member  88 . The creation of point contacts instead of a complete face to face or line contact by the plurality of engagement surfaces reduces or minimizes friction between first member  86  and second member  88 , thereby facilitating the relative rotation between the two components. 
       FIG. 13  is a side elevational view and  FIG. 14  is a front elevational view of pivot assembly  72 . As seen in  FIGS. 13 and 14 , pivot assembly  72  includes first conduit member  100  and second conduit member  102  that are rotatably coupled to one another as described herein. 
       FIG. 15  is a front isometric view,  FIG. 16  is a front elevational view, and  FIG. 17  is a bottom isometric view of first conduit member  100 . First conduit member  100  includes cylindrical connector portion  104  defining first fluid chamber  106  ( FIG. 17 ). First and second semi-cylindrical mating portions  108 A,  108 B are coupled to cylindrical connector portion  104  and define a gap  110  between them. In addition, each semi-cylindrical mating portion  108 A,  108 B defines an internal fluid chamber that is fluidly coupled to first fluid chamber  106 . Also, each semi-cylindrical mating portion  108 A,  108 B includes an arced surface  112 A,  112 B connected to a flat surface  114 A,  114 B. An orifice  116 A,  116 B is provided in each flat surface  114 A,  114 B and provides fluid access to each internal fluid chamber. First conduit member  100  thus defines a fluid path that extends from cylindrical connector portion  104  to semi-cylindrical mating portions  108 A,  108 B to orifices  116 A,  116 B. In an alternative embodiment, one of first and second semi-cylindrical mating portions  108 A,  108 B may be solid and therefore not include an internal fluid chamber that is fluidly coupled to first fluid chamber  106 . In this embodiment, first conduit member  100  will defines a fluid path that extends from cylindrical connector portion  104  to the non-solid semi-cylindrical mating portions  108 A,  108 B to associated orifices  116 A,  116 B. 
       FIG. 18  is a side elevational view and  FIG. 19  is a front isometric view of second conduit member  102 . Second conduit member  102  includes cylindrical connector portion  118  defining first fluid chamber  120 . In addition, cylindrical connector portion  118  includes a snap ring connector portion  78  for securing elbow conduit  70 , once assembled as described herein, to frame  14  or another frame or faceplate. More specifically, snap ring connector portion  78  includes rings  80 ,  82  which define a groove  84  therebetween. Groove  84  is structured to receive split ring washer  74  ( FIG. 9 ) after snap ring connector portion  78  is inserted through the opening provided in frame  14  (or a similar opening in another frame or faceplate) to keep snap ring connector portion  78  from pulling back through the opening. 
     A mating portion  122  is coupled to cylindrical connector portion  118  and defines a second fluid chamber  124  ( FIG. 19 ) that is fluidly coupled to first fluid chamber  120 . Mating portion  122  includes first and second flat surfaces  126 A,  126 B positioned opposite one another. A port member  128 A,  128 B extends from each flat surface  126 A,  126 B and provides fluid access to second fluid chamber  124 . Second conduit member  102  thus defines a fluid path that extends from cylindrical connector portion  118  to mating portion  122  to port members  128 A,  128 B. In an alternative exemplary embodiment, one of port members  128 A,  128 B may be closed off with a plug or the like, in which case second conduit member  102  will define a fluid path that extends from cylindrical connector portion  118  to mating portion  122  to the open one of the port members  128 A,  128 B. 
     Pivot assembly  72  is assembled by inserting mating portion  122  of second conduit member  102  into gap  110  of first conduit member  100  and inserting port members  128 A,  128 B into orifices  116 A,  116 B. When this is done, flat surfaces  126 A,  126 B will engage flat surfaces  114 A,  114 B, and first conduit member  100  will be able to rotate relative to second conduit member  102  over at least 180 degrees. More specifically, first conduit member  100  will be able to rotate about longitudinal axes through  128 A,  128 B, which longitudinal axes are perpendicular to the longitudinal axis of both cylindrical connector portion  104  and cylindrical connector portion  118 . 
     Furthermore, the remainder of elbow conduit  70  may be assembled as shown in  FIG. 8  by inserting first member  86  of swivel connector assembly  76  into cylindrical connector portion  104  of first conduit member  100  of pivot assembly  72 . Snap ring connector portion  78  may then be inserted into the opening in frame  14 . Once so connected, elbow conduit  70  is free to rotate within frame  14  about the longitudinal axis of second conduit member  102 . In addition, after elbow conduit  70  is connected to frame  14  as just described, the delivery conduit or tube of patient circuit  6  can be connected to swivel connector assembly  76 . 
     Thus, when fully assembled, elbow conduit  70 , and thus the delivery conduit or tube of patient circuit  6  coupled thereto, is able to rotate  360  degrees about the longitudinal axis of second conduit member  102 . In addition, first conduit member  100 , and thus the delivery conduit or tube of patient circuit  6  coupled thereto, is able to simultaneously rotate at least 180 degrees about an axis that is perpendicular to the longitudinal axis of second conduit member  102 . This simultaneous, multi-axis rotation capability facilitates the movement of the tubing of patient circuit  6 , and as a result will reduce the adverse effects of tubing torque, resulting in increased mask stability and a decreased likelihood of seal loss. 
     Alternatively, the first conduit member  100  side of pivot assembly  72  could be attached to frame  14  and the second conduit member  102  side of pivot assembly  72  could be attached to patient circuit  106  with the same functionality being provided. 
       FIG. 20  is a side view and  FIG. 21  is an isometric view of an elbow conduit  130  according to another alternative exemplary embodiment of the invention. Elbow conduit  130  may be coupled to patient interface device  8  by being inserted into an opening provided in frame  14  (or an alternative patient interface device by being inserted into an opening provided in the frame or faceplate thereof), and may coupled to a gas delivery conduit or tube of patient circuit  6  so that a breathing gas can be delivered from pressure generating device  4  to patient interface device  8 . In addition, as described in greater detail herein, elbow conduit  130 , like elbow conduits  10  and  70 , is structured to provide for simultaneous rotation in multiple axes with respect to frame  14 . 
     Elbow conduit  130  includes a first conduit member  132  and a second conduit member  134  that are rotatably coupled to one another as described herein. First conduit member  132  is the part of elbow conduit  130  that provides the coupling to frame  14 , and second conduit member  134  is the part of elbow conduit  10  that provides the coupling to patient circuit  6 . 
       FIG. 22  is an isometric view of first conduit member  132 , which is a female type connector. First conduit member  132  includes cylindrical connector portion  136  defining a first fluid chamber. A bottom lip  138  is provided at the bottom of cylindrical connector portion  136 , and a top lip  140  is provided at the top of cylindrical connector portion  136 . An angled mating portion  142  is coupled to cylindrical connector portion  136  and defines a second fluid chamber that is fluidly coupled to the first fluid chamber of first conduit member  132 . Mating portion  142  includes a back surface  144  connected to an angled surface  146 . Angled surface  146  is disposed at an angle with respect to the flat plane defining the top of cylindrical connector portion  136 . In the exemplary embodiment, that angle may range from 30 degrees to 90 degrees (at 90 degrees, it will be similar to that shown in the embodiment of  FIGS. 1-7 ). In the illustrated embodiment, the angle at which angled surface  146  is disposed is 45 degrees. The significance of this is described elsewhere herein. An orifice  148  is provided in angled surface  146  and provides fluid access to the second fluid chamber of first conduit member  132 . A plurality of apertures (not shown) may be provided in back surface  144  for forming an exhaust port. First conduit member  132  thus defines a fluid path that extends from cylindrical connector portion  136  to angled mating portion  142  to orifice  148 . 
       FIG. 23  is an isometric view of second conduit member  134 , which is a male type connector. Second conduit member  134  includes a cylindrical connector portion  150  defining a first fluid chamber. A bottom lip  152  is provided at the bottom of cylindrical connector portion  150 , and a top lip  154  is provided at the top of cylindrical connector portion  150 . An angled mating portion  156  is coupled to cylindrical connector portion  150  and defines a second fluid chamber that is fluidly coupled to the first fluid chamber. Mating portion  156  includes a back surface  158  connected to an angled surface  160 . Angled surface  160  is disposed at an angle with respect to the flat plane defining the top of cylindrical connector portion  150  that matches the angle of angled surface  146  of first conduit member  132 . In the exemplary embodiment, that angle may range from 30 degrees to 90 degrees (at 90 degrees, it will be similar to that shown in the embodiment of  FIGS. 1-7 ). In the illustrated embodiment, the angle at which angled surface  160  is disposed is 45 degrees. The significance of this is described elsewhere herein. A male port member  162  extends from angled surface  160  and provides fluid access to the second fluid chamber of second conduit member  134 . Second conduit member  134  thus defines a fluid path that extends from cylindrical connector portion  150  to mating portion  156  to port member  162 . In one particular, non-limiting exemplary embodiment, second conduit member  134  may further include an entrainment valve. 
     Elbow conduit  130  is assembled by inserting port member  162  of second conduit member  134  into orifice  148  of first conduit member  132 . When this is done, angled surfaces  146 ,  160  will engage one another ( FIGS. 20 and 21 ), and second conduit member  134  will, in the exemplary embodiment, be able to rotate relative to first conduit member  132  over 360 degrees. More specifically, second conduit member  134  will be able to rotate about longitudinal axes through port member  162  and orifice  148 . 
     Alternatively, port member  162  may be replaced by an orifice and orifice  148  may be replaced by a port member such that the port member of first conduit member  132  is inserted into the orifice of second conduit member  134  during assembly. In either exemplary embodiment, the port member is held within the orifice by a snap fit. In one particular exemplary embodiment, the port member may be provided with slots to facilitate the snap fit insertion into the orifice. 
     Once assembled as just described, cylindrical connector portion  136  of first conduit member  132  may be inserted into the opening in frame  14 . Once so connected, elbow conduit  130  is free to rotate within frame  14  about the longitudinal axis of first conduit member  132 . In addition, after elbow conduit  130  is connected to frame  14  as just described, the delivery conduit or tube of patient circuit  6  can be connected to cylindrical connector portion  150  of second conduit member  134 . In the exemplary embodiment, cylindrical connector portion  150  is sized to fit either a standard 15 mm hose or a standard 22 mm hose. In addition, a swivel connector may or may not be used for this connection. 
     Thus, when fully assembled as shown in  FIGS. 20 and 21 , elbow conduit  130 , and, thus, the delivery conduit or tube of patient circuit  6  coupled thereto, is able to rotate  360  degrees about the longitudinal axis of first conduit member  132 . In addition, second conduit member  134 , and thus the delivery conduit or tube of patient circuit  6  coupled thereto, is able to simultaneously rotate about an axis that is transverse to the longitudinal axis of first conduit member  132 . In particular, second conduit member  134  is able to rotate from a first position wherein the longitudinal axis of second conduit member  134  is aligned with and parallel to the longitudinal axis of second conduit member  134  as seen in  FIG. 20 and 21 , to a second position wherein the longitudinal axis of second conduit member  134  perpendicular to the longitudinal axis of second conduit member  134 . This simultaneous, multi-axis rotation capability facilitates the movement of the tubing of patient circuit  6 , and as a result will reduce the adverse effects of tubing torque, resulting in increased mask stability and a decreased likelihood of seal loss. 
     It can be appreciated that the present invention facilitates movement of the tubing between the ventilator or pressure support device and the patient interface device in order to reduce the effects of tubing torque to increase mask stability and decrease the likelihood of loss of seal. 
     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. 
     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.