Abstract:
A swivel exhaust conduit for rotatably connecting a patient mask to the delivery conduit of a positive pressure air supply. The swivel exhaust conduit design provides an exhaust port that utilizes the rotating bearing of the swivel conduit&#39;s rotating two-piece design for permitting and directing exhaust of CO 2  laden air. A baffle chamber formed in the clearance of the two pieces provides an area where noise is reduced. As CO 2  laden exhaust exits the swivel exhaust conduit, it is directed away from the patient mask and down the outside of the delivery conduit via a slit pattern on the swivel conduit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority under 35 U.S.C. § 120 as a Continuation of U.S. patent application Ser. No. 09/337,595 filed Jun. 21, 1999 now U.S. Pat. No. 6,615,830, which is a Continuation of U.S. patent application Ser. No. 08/810,332 filed Feb. 27, 1997, now U.S. Pat. No. 5,937,851. 

   FIELD OF INVENTION 
   The present invention relates to providing a respiratory mask with a two-piece swivel conduit that uses the rotating bearing of its swivel design to permit and preferably direct carbon dioxide (CO.sub.2) laden exhaust from the patient breathing circuit. 
   BACKGROUND OF THE INVENTION 
   A variety of delivery systems are known that deliver gas at positive pressure for consumption by the user. The uses and applications of such systems vary. Some such systems have been developed for the treatment of sleep apnea. 
   Sleep apnea syndrome is an episodic upper airway obstruction during sleep. As a consequence, there is repeated interruption of sleep in the patient. Positive airway pressure (PAP) devices have been developed to treat this disorder. A typical PAP device comprises a flow generator (e.g., a blower) which delivers gas via a delivery conduit to a patient interface, such as a mask. 
   Several types of respiratory face masks for delivering gas to a patient are known. One such mask incorporates ports in the body of the mask to provide an exhaust leak to purge the system of CO.sub.2 laden air. However, several drawbacks are associated with ports in the body of the mask. For example, air exiting the mask ports may create noise or blow on the patient, causing discomfort. 
   Respironics, Inc. of Murrysville, Pa. has developed and manufactured a swivel conduit having exhaust vents under the name Whisper Swivel® Exhalation Port. See  FIG. 1   a . This two-piece swivel conduit not only provides a swivel connection between the mask and the delivery conduit but also includes a plurality of downwardly directed exhaust slits. The slit configuration of the vents acts to reduce noise and direct the CO 2  laden exhaust away from the patient. 
   SUMMARY OF THE INVENTION 
   The improved swivel conduit rotatably connects a patient mask to the delivery conduit of the present invention of a positive pressure air supply. The improved design provides an exhaust vent for purging the system of CO 2  laden air that utilizes the rotating bearing of its two-piece design. A baffle chamber in the design reduces the intensity of the sound generated. As CO 2  laden exhaust exits the swivel conduit, it is directed away from the patient mask and down the outside of the delivery conduit via a slit pattern on the swivel conduit. The unique two-peice bearing design may be easily disassembled for cleaning. 
   The swivel conduit design directs CO 2  laden expiratory exhaust away from the patient in a diffused air flow stream along the delivery conduit. This diffused air flow provides for a less perceptible sensation to the patient or sleeping partner. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will become more readily apparent from the following description of preferred embodiments thereof shown, by way of example only, in the accompanying drawings, wherein: 
       FIG. 1   a  is an exploded perspective view of a Whisper Swivel® device assembled with a respiratory mask and delivery conduit; 
       FIG. 1   b  is an exploded perspective view of a swivel conduit according to a first embodiment of the present invention assembled with a respiratory mask and delivery conduit; 
       FIG. 2  is an exploded perspective view of the swivel conduit device according to a first embodiment of the present invention; 
       FIG. 3  is a cross-sectional view of the swivel conduit according to the first embodiment of the present invention; 
       FIG. 4  is top plan view of the mask connection piece according to the first embodiment of the present invention; 
       FIG. 5  is a cross-sectional view of the swivel conduit according to a second embodiment of the present invention; 
       FIG. 6  is a cross-sectional view (rotated 45° as compared to  FIG. 5 ) of the swivel conduit according to a third embodiment of the present invention; 
       FIG. 7  is a cross-sectional view of the swivel conduit according to a fourth preferred embodiment of the present invention; and 
       FIG. 8  is a cross-sectional view of the swivel conduit according to a fifth embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   There is generally indicated at  10  in  FIG. 1  a swivel conduit of conventional Whisper Swivel® Exhalation Port device manufactured by Respironics, Inc. Swivel conduit  10  has a mask connection piece  12 , which is received within one end of an L-shaped conduit  14  attached to a respiratory mask  16 , and a delivery conduit piece  18 , which is received within one end of a delivery conduit  20 , to deliver pressurized air from a positive airway pressure device or other ventilatory device (not shown). A plurality of parallel slits  22  on the mask connection piece  12  are directed downwardly towards the delivery conduit end  24  of the swivel conduit  10  to permit purging of CO 2  laden expiratory exhaust. The mask connection piece  12  and the delivery conduit piece  18  are rotatably coupled to each other, thus, allowing the mask  16  to rotate relative to the delivery conduit  20 . 
     FIGS. 1   b ,  2 ,  3  and  4  illustrate a first embodiment of an improved swivel exhaust device  100 . The improved two-piece design has a mask connection piece  112 , which is received within one end of an L-shaped mask conduit  14 , and a delivery conduit piece  114 , which is received within one end of the delivery conduit  20 . The mask connection piece  112  and the delivery conduit piece  114  are rotatably coupled to each other. Discharge of CO 2  laden expiratory exhaust is permitted through the clearance  116  between the mask connection piece  112  and the delivery conduit piece  114 . 
   The mask connection piece  112  generally comprises a tubular mask connection end  118  which is received in the L-shaped mask conduit  14 , an intermediate stepped portion  120  having a larger diameter than the mask connection end  118 , and a radial exhaust end  122  opposite the mask connection end  118 . The stepped portion  120  is joined to the mask connection  118  end by a sloped portion  124  whose diameter increases from the mask connection end diameter to that of the stepped portion diameter. The exhaust end  122  also has a sloped portion  126  in which the diameter increases to that of an annular portion  128  having a diameter larger than the stepped portion diameter. This design of the mask connection piece  112  helps direct CO 2  laden exhaust out and away from the device  100 . Raised portions  130  on the interior surface of the sloped portion  126  and annular portion  128  of the exhaust end  122  form a slit pattern which further directs CO 2  laden exhaust away from the patient ( FIG. 4 ). There are preferably three narrower raised portions  130  and one wider raised portion  132 . As CO 2  laden exhaust exits the device  100 , it is directed away from the patient mask  16  via the slit pattern down the outside of the delivery conduit  20 . In use, the wider raised portion  132  can be positioned nearest the patient side of the mask connection piece  112  so that CO 2  laden exhaust is directed away from the patient. 
   The exterior surface of the sloped  126  and annular  128  portions of the exhaust  122  end have raised serrations  134  to prevent intentional blocking of the CO 2  laden exhaust. However, the exterior surface in the preferred embodiment is formed without the serrations  134 . 
   The delivery conduit piece  114  includes a tapered delivery conduit  136  end, which is received within the delivery conduit  20 , and a swivel connection end  138 , which is rotatably received within the mask connection end  118  of the mask connection piece  112 . The swivel connection end  138  preferably has four longitudinal slots  140  forming four retaining arms  142 ,  144 . Two of the retaining arms  144  that are opposite each other preferably are longer than the other two retaining arms  142 . All four arms  142 ,  144  have radial outwardly projecting segments  146  to retain the delivery conduit piece  114  within the mask connection piece  112 . By pressing inwardly on the radial segments  146  of the two longer retaining arms  144 , the mask connection piece  112  and the delivery conduit piece  114  may be easily separated. The delivery conduit piece  114  has a locating portion  148  joining an intermediate stepped portion  150  and the swivel connection end  138 , and an exhaust portion  152  disposed between the stepped portion  150  and the delivery conduit end  136 . When the two pieces  112 ,  114  are assembled, the two longer retaining arms  144  form cantilever springs which load, center and locate the sloped portion  124  of the stepped portion of the mask connection piece  112  against the locating portion  148  of the delivery conduit piece  114 . 
   The exhaust portion  152  of the delivery conduit piece comprises a sloped portion  154  of increasing diameter and an annular portion  156  of a diameter larger than the stepped portion diameter. The area between the stepped portions  120 ,  150  of the mask connection piece  112  and the delivery conduit piece  114  forms a baffle chamber  158  through which the CO 2  laden exhaust flows. The baffle chamber  158  gradually reduces the noise of the CO 2  laden exhaust being purged from the device  100 . 
   Alternative embodiments are shown in  FIGS. 5-8  with the embodiment of  FIG. 7  being the preferred embodiment. Like elements will be designated by like reference numerals. 
   A swivel conduit  200  in accordance with a second embodiment of the present invention is shown in  FIG. 5 . In this embodiments, the stepped portion of the delivery conduit piece  214  includes a raised baffle  250  to reduce noise. In this embodiment, as well as in the embodiments illustrated in  FIGS. 6 and 7 , the two shorter retaining arms  242  preferably do not have radial segments. Alternately, in an unillustrated embodiment, all retaining arms are the same longer length with the two arms which are pressed inwardly for disassembly having locating notches. 
   A swivel conduit  300  in accordance with a third embodiment of the present invention is shown in  FIG. 6 . In this embodiment 1  spaced radial holes  360  are provided (preferably four) in the stepped portion  350  of the delivery conduit piece  314  to provide an additional path for CO 2  laden exhaust between the interior of the delivery conduit piece  314  and the baffle chamber  358 . Hole bosses  362  protrude inwardly to divert fluids or secretions around the holes. In this embodiment, CO 2  laden exhaust flow is determined by both the holes  360  and the clearance  316  between the mask connection piece  312  and the delivery conduit piece  314 . 
   In a swivel conduit  400  of a fourth preferred embodiment illustrated in  FIG. 7  of the present invention, the delivery conduit piece  414  includes a baffle portion  452  as described in accordance with  FIG. 5 . Also, each of the longitudinal slots  440  of the swivel connection end  438  ends in a hole  464 . These holes  464  are preferably angled for manufacturing purposes but could be disposed radially. These holes  464  provide an improved exhaust entrance to the baffle chamber  458 . 
   In a fifth embodiment 500 of the present invention illustrated in  FIG. 8 , the mask connection piece  512  also comprises an L-shaped portion  566  for attachment to the respiratory mask  16 , thus, reducing the need for a separate L-shaped conduit  14 . In this design, a single retaining arm  542  attaches the pieces  512  and  514  together. Likewise, it is contemplated that the delivery conduit piece  514  could be unitarily formed with the delivery conduit  20 . 
   The present invention provides several advantages over that of the prior art. Its unique design provides optimum comfort through improved exhaust rates and reduced noise. The pieces, which can be formed by injection molding 1  do not require additional processing, thus reducing manufacturing costs. The two-piece design is easily disassembled for cleaning and discourages exhaust vents from being sealed off. The swivel action also allows for the unplugging of secretions. 
   Although the invention has been described in detail for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention as it may be limited by the claims.