A device for maintaining an airway in a patient comprises mask having a peripheral portion that forms a seal with the larynx when the mask is positioned in the laryngo pharynx to thereby prevent ingress of extraneous fluids into the larynx airway tube connected to or formed with the mask for passing gas to the larynx when the mask is properly inserted into the laryngo pharynx. The peripheral portion of the mask includes a soft, flexible portion that contacts tissues surrounding the laryngeal opening when the device is inserted into a patient, the soft, flexible portion being arranged whereby application of pressurized gas to the airway tube urges the soft, flexible portion into contact with the tissues surrounding the laryngeal opening or the pharyngeal wall.