Patient interfaces

A patient interface comprising:

• a mask assembly configured to be coupled with an elbow assembly for delivering a pressurized gas to a patient;
• the elbow assembly comprising:
• a first leg configured to connect to a source of the pressurized gas at a first end of the elbow assembly;
• and
• a second leg configured to swivelably connect to the mask assembly, the second leg comprising:
• a second end of the elbow assembly configured to insertably interface with the mask assembly;
• an outer conduit and an inner conduit fixed within the outer conduit, a first tubular section of the outer conduit disposed radially outward of a second tubular section of the inner conduit, the inner conduit extending towards the second end of the elbow assembly from a front wall of the outer conduit, a distal portion of the second tubular section disposed within a straight section of the second leg;
• a first flow path defined between the inner conduit and the outer conduit, the first flow path accommodating a first flow of gases in a first direction;
• a second flow path defined within the inner conduit, the second flow path accommodating a second flow of gases in a second direction, the first direction being directly opposite the second direction in at least a portion of the second leg;
• and
• a diffuser comprising a plurality of exhaust vents in the front wall of the outer conduit;
• wherein the first tubular section of the outer conduit has a first length and the second tubular section of the inner conduit has a second length, the first length being greater than the second length.

A patient interface comprising:

• a mask assembly configured to be coupled with an elbow assembly for delivering a pressurized gas to a patient;
• the elbow assembly comprising:
• a first portion configured to connect to a source of the pressurized gas at a first end of the elbow assembly;
• and
• a second portion configured to swivelably connect to the mask assembly, the second portion comprising a second end of the elbow assembly, an outer wall of the second portion having a plurality of exhaust vent holes extending therethrough, a portion of the outer wall configured to be insertable within the mask assembly, and an inner tubular wall fixed within a tubular portion of the outer wall, the inner tubular wall formed as an integral unit with the outer wall such that both the inner tubular wall and the outer wall swivel with respect to the mask assembly, a circumferential end portion of the inner tubular wall extending within the tubular portion of the outer wall in the second portion;
• wherein the inner tubular wall extends towards the second end of the elbow assembly from adjacent the plurality of exhaust vents and the inner tubular wall shields the plurality of exhaust vent holes from an inspiratory gas flow from the source of the pressurized gas;
• and wherein an end of the outer wall is offset in an axial direction away from the plurality of exhaust vents from the circumferential end portion of the inner tubular wall.