Devices for providing respiratory therapy to a patient are disclosed. One device includes first and second elongated lumens and a nosepiece. The elongated lumens each have a constant internal diameter. The nosepiece portion has a third lumen and a fourth lumen. The third and fourth lumens have constant internal diameters equal to those of the first and second lumens. The third and fourth lumens have inlet ends adapted to be connected to the outlet ends of the first and second lumens without constricting the internal diameter of the first and second lumens. The third and fourth lumens are configured to receive first and second flows of breathing gas from the first and second lumens and deliver the flows of breathing gas to outlets end of the third and fourth lumens. The second flow of breathing gas is maintained separate from the first flow of breathing gas within the nosepiece portion.
