Nasal interface

Abstract

A nasal cannula for use in a system for providing a flow of respiratory gases to a user is described. The nasal cannula comprises a body made from a pliable material. The body has an inlet and at least one nasal prong fluidly connected to the inlet. In use a conduit providing a flow of gases to the cannula is connected to the inlet, and the nasal prong is inserted into a user's nostril. The cannula is arranged to direct the flow of gases from the nasal prong towards the front wall of the user's nasal passage within the user's nose.

1 . (canceled) 
     
     
         2 . A heated, respiratory gas delivery conduit assembly for use in a system for providing a flow of humidified respiratory gases to a user, the heated, respiratory gas delivery conduit assembly comprising:
 an inspiratory gas supply conduit having a gas conduit upstream portion configured to be connectable to a humidifying inspiratory gas supply unit and to receive gas from the humidifying inspiratory gas supply unit, the inspiratory gas supply conduit also comprising a gas conduit downstream portion configured to be connected to a respiratory gas patient interface;   a heating element extending along an inner portion of the inspiratory gas supply conduit between the gas conduit upstream portion and the gas conduit downstream portion, the heating element being configured to prevent condensation of humidified gases occurring within inspiratory gas supply conduit; and   a flow restrictor connected to the gas conduit downstream portion of the inspiratory gas supply conduit and with the inspiratory gas supply conduit, defining a gas flow path from the gas conduit upstream portion, through the gas conduit downstream portion and through the flow restrictor, the flow restrictor comprising a flow restrictor inlet portion, a flow restrictor outlet portion, and a constricted orifice disposed downstream from the flow restrictor inlet portion, the flow restrictor inlet portion comprising an outer diameter matched to an internal diameter of the gas conduit downstream portion, the flow restrictor inlet portion defining a first inner cross sectional area of the gas flow path, the constricted orifice comprising an orifice plate with a reduced area orifice defining a second cross sectional area of the gas flow path so as to partially occlude the gas flow path, the second cross sectional area is less than one half of the first cross sectional area so as to decouple the portions of the gas flow path upstream from the constricted orifice from portions of the gas flow path downstream from the constricted orifice and such that the constricted orifice remains a dominant flow restriction in the gas flow path when a patient interface is fluidically connected to the flow restrictor outlet portion.   
     
     
         3 . The heated, respiratory gas delivery conduit assembly of  claim 2 , additionally comprising a patient inspiratory gas supply conduit connected to the flow restrictor outlet portion, the patient inspiratory gas supply conduit having a third cross sectional than is larger than the second cross sectional area. 
     
     
         4 . The heated, respiratory gas delivery conduit assembly of  claim 3 , wherein the patient inspiratory gas supply conduit comprises a breathable wall. 
     
     
         5 . The heated, respiratory gas delivery conduit assembly of  claim 2 , additionally comprising a non-sealing patient interface having a resilient, flexible, pliable body portion. 
     
     
         6 . A respiratory gas delivery conduit assembly for use in a system for providing a flow of humidified respiratory gases to a user, the respiratory gas delivery conduit assembly comprising:
 an inspiratory gas supply conduit having a gas conduit upstream portion configured to be connectable to a humidifying inspiratory gas supply unit and to receive gas from the humidifying inspiratory gas supply unit, the inspiratory gas supply conduit also comprising a gas conduit downstream portion;   a heating element extending along an inner portion of the inspiratory gas supply conduit between the gas conduit upstream portion and the gas conduit downstream portion; and   a flow restrictor connected to the downstream portion of the inspiratory gas supply conduit and with the inspiratory gas supply conduit, defining a gas flow path from the gas conduit upstream portion, through the gas conduit downstream portion and through the flow restrictor, the flow restrictor comprising a flow restrictor inlet portion, a flow restrictor outlet portion, and a constricted orifice disposed downstream from the flow restrictor inlet portion, the flow restrictor inlet portion defining a first inner cross sectional area of the gas flow path, the constricted orifice comprising a reduced area orifice defining a second cross sectional area of the gas flow path so as to partially occlude the gas flow path.   
     
     
         7 . The heated, respiratory gas delivery conduit assembly of  claim 6 , additionally comprising a patient inspiratory gas supply conduit connected to the flow restrictor outlet portion, the patient inspiratory gas supply conduit having a third cross sectional than is larger than the second cross sectional area. 
     
     
         8 . The heated, respiratory gas delivery conduit assembly of  claim 7 , wherein the patient inspiratory gas supply conduit comprises a breathable wall. 
     
     
         9 . The heated, respiratory gas delivery conduit assembly of  claim 6 , additionally comprising a non-sealing patient interface having a resilient, flexible, pliable body portion. 
     
     
         10 . The heated, respiratory gas delivery conduit assembly of  claim 6 , wherein the gas conduit downstream portion is configured to be connected to a respiratory gas patient interface. 
     
     
         11 . The heated, respiratory gas delivery conduit assembly of  claim 6 , wherein the heating element is configured to prevent condensation of humidified gases occurring within inspiratory gas supply conduit. 
     
     
         12 . The heated, respiratory gas delivery conduit assembly of  claim 6 , wherein the flow restrictor inlet portion comprises an outer diameter matched to an internal diameter of the gas conduit downstream portion. 
     
     
         13 . The heated, respiratory gas delivery conduit assembly of  claim 6 , wherein the constricted orifice comprises an orifice plate defining the reduced area orifice. 
     
     
         14 . The heated, respiratory gas delivery conduit assembly of  claim 6 , wherein the second cross sectional area is less than one half of the first cross sectional area. 
     
     
         15 . The heated, respiratory gas delivery conduit assembly of  claim 14 , wherein the second cross sectional area sufficiently smaller than the first cross sectional area so as to decouple the portions of the gas flow path upstream from the constricted orifice from portions of the gas flow path downstream from the constricted orifice and such that the constricted orifice remains a dominant flow restriction in the gas flow path when a patient interface is fluidically connected to the flow restrictor outlet portion. 
     
     
         16 . A respiratory gas delivery conduit assembly for use in a system for providing a flow of humidified respiratory gases to a user, the respiratory gas delivery conduit assembly comprising:
 an inspiratory gas supply conduit having a gas conduit upstream portion and a gas conduit downstream portion;   a heating element extending within the inspiratory gas supply conduit; and   a flow restrictor connected to the downstream portion of the inspiratory gas supply conduit, the flow restrictor comprising a flow restrictor inlet portion, a flow restrictor outlet portion, and a constricted orifice disposed downstream from the flow restrictor inlet portion, the flow restrictor inlet portion defining a first cross sectional gas flow area, the constricted orifice defining a second cross sectional gas flow area, and the flow restrictor outlet portion defining a third cross sectional gas flow area, the second cross sectional gas flow area being less than both the first and third cross sectional gas flow areas.   
     
     
         17 . The heated, respiratory gas delivery conduit assembly of  claim 16 , additionally comprising a patient inspiratory gas supply conduit connected to the flow restrictor outlet portion, the patient inspiratory gas supply conduit having a fourth cross sectional gas flow area that is larger than the second cross sectional gas flow area. 
     
     
         18 . The heated, respiratory gas delivery conduit assembly of  claim 17 , wherein the patient inspiratory gas supply conduit comprises a breathable wall. 
     
     
         19 . The heated, respiratory gas delivery conduit assembly of  claim 16 , additionally comprising a non-sealing patient interface having a resilient, flexible, pliable body portion. 
     
     
         20 . The heated, respiratory gas delivery conduit assembly of  claim 16 , wherein the gas conduit downstream portion is configured to be connected to a respiratory gas patient interface. 
     
     
         21 . The heated, respiratory gas delivery conduit assembly of  claim 16 , wherein the heating element is configured to prevent condensation of humidified gases occurring within inspiratory gas supply conduit. 
     
     
         22 . The heated, respiratory gas delivery conduit assembly of  claim 16 , wherein the flow restrictor inlet portion comprises an outer diameter matched to an internal diameter of the gas conduit downstream portion. 
     
     
         23 . The heated, respiratory gas delivery conduit assembly of  claim 16 , wherein the constricted orifice comprises an orifice plate with an orifice comprising the second cross sectional gas flow area. 
     
     
         24 . The heated, respiratory gas delivery conduit assembly of  claim 16 , wherein the second cross sectional area is less than one half of the first cross sectional area. 
     
     
         25 . The heated, respiratory gas delivery conduit assembly of  claim 24 , wherein the second cross sectional area is sufficiently smaller than the first cross sectional area so as to decouple the portions of the gas flow path upstream from the constricted orifice from portions of the gas flow path downstream from the constricted orifice and such that the constricted orifice remains a dominant flow restriction in the gas flow path when a patient interface is fluidically connected to the flow restrictor outlet portion. 
     
     
         26 . The heated, respiratory gas delivery conduit assembly of  claim 16 , wherein the gas conduit upstream portion is configured to be connected to a humidifying inspiratory gas supply unit and to receive gas from the humidifying inspiratory gas supply unit.