An assembly for modifying airflow into a nasopharyngeal airway or trachea of a patient. A valve assembly is adapted to attach to an airflow generator, wherein the airflow generator is a continuous blower of a type producing a constant head of pressurized air. One or more drive gears are attached to and powered by a servo motor. A valve seal within the feed tube is connected to and operable by the drive gears, the valve seal adapted to cycle within the feed tube across the outlet. A controller circuit is connected to the servo motor for operating the servo motor incrementally, wherein pressurized air from said airflow generator continuously enters said feed tube from said inlet but travels to said patient only when said servo motor causes said valve seal to move such that said pressurized air is converted into a single, repeatable burst.
