Described here are devices for altering the flow of air in a respiratory cavity such as the mouth and nostrils of the nose. These methods and devices may be useful for affecting a physiologic benefit in patients suffering from a variety of medical diseases, particularly those that may benefit from “pursed-lip”...http://www.google.es/patents/US7992564?utm_source=gb-gplus-sharePatente US7992564 - Respiratory devices
