A respiratory device (10,110,210,310,410,610,710) for delivering gas to a patient comprises a gases passageway (30,130,230,330,430,630,730) having proximal and distal ends, and a supplementary gas inlet (50,150,250,350,450,650,750) in a side wall of the gases passageway. The supplementary gas inlet (50,150,250,350,450,650,750) is adapted to direct gas along an interior surface of the gases passageway(30,130,230,330,430,630,730), such that the gas follows a generally helical path towards the distal end of the gases passageway (30,130,230,330,430,630,730).
