A supplemental gas delivery device is described for a mask assembly having at least one supplemental gas port, the at least one supplemental gas port including an aperture in communication with an interior of the mask assembly. The mask assembly may include an aperture communicating with an interior of the mask assembly, and a cannula for communicating with the supplemental gas port. The cannula is positioned to deliver supplemental gas adjacent to the patients nares and/or mouth, to increase an efficacy of treatment for the patient by more directly applying the flow of supplemental gas to the patients nares. An optional bridging portion may be included to provide a connection between supplemental gas port and the cannula.
