Abstract: The present invention discloses both a method of operating CPAP apparatus, and the apparatus itself in which a breathable gas delivery device, or mask (1), is connected to a gas supply pump (14) via a conduit which includes a restriction to gas flow such as a small bore portion (3). A pressure transducer (11) is used to sense the gas pressure at the patient's nose and the transducer output is used to servo-control the pump (14) to maintian the sensed pressure substantially constant.

Abstract: A combination mouth and nasal mask (40) for assisted respiration or CPAP is disclosed.The combination mask (40) has a frame (42) to the rear side of which is mounted a separate nasal cushion (44) and mouth cushion (46). Both the nasal cushion (44) and the mouth cushion (46) separately form a rolled edge seal around the patient's face in the vicinity of the nose and in the vicinity of the lips. Inlet air is communicated from within the housing (48) to the mouth chamber, circumscribed by the mouth cushion (46) by means of one or more interconnecting tubes (62).The proportion of air communicated to the mouth chamber (48) is controlled by the sizing and number of the tube(s), thus providing for free flow of air, restricted flow of air and pressure equalisation, or zero flow of air.A mouth mask (10) for assisted respiration or CPAP also is disclosed.