Abstract: A mask for the delivery of a medical gas under positive pressure. The engagement surface is generally circular in shape and is sufficiently rigid that operatively, when a suitable retention force is applied to the mask, an effective seal is produced at the interface of the engagement surface and the surrounding tissue primarily by deformation of the surrounding tissue.

Abstract: A mask for the delivery of a medical gas under positive pressure. The engagement surface is generally circular in shape and is sufficiently rigid that operatively, when a suitable retention force is applied to the mask, an effective seal is produced at the interface of the engagement surface and the surrounding tissue primarily by deformation of the surrounding tissue.

Abstract: A mask for the delivery of a medical gas under positive pressure, the mask including a single shell forming a chamber having an outlet, a first passage connecting the chamber to the exterior of the mask, a sealing recess isolated from the chamber and open to allow engagement with the face of a user, and extending around the periphery of the outlet, and a second passage connecting the sealing recess to the exterior of the mask, the arrangement being such that operatively the mask may be placed on a user so as to cover the airway, suction may be connected to the second passage so that the sealing recess seals the mask against the face of the user, and a medical gas may be supplied to the first passage for delivery through the outlet to the airway of the user.