A nasal continuous positive airway pressure (CPAP) device 100 includes a neck region 200 connected to a mask or nasal prong； and an elongated flexible tube 300. The elongated flexible tube 300 comprises co-axial inner 310 and outer 320 tubes. The inner 310 and outer 320 tubes are spaced to define a first lumen 330 within the outer tube 320. A second lumen 340 is defined by the inner tube wall alone. The second lumen 340 is configured to be connected to a breathable gas supply such as air or oxygen at the distal end 304 of the elongated flexible tube 300, and to the neck region 200 at the proximal end 302 of the elongated flexible tube 300. The first lumen 330 is configured to be connected to the neck region 200 at the proximal end 302 of the elongated flexible tube 300.
