An assembly for modifying airflow into a nasopharyngeal airway of a patient. A valve assembly is adapted to attach to an airflow generator. A solenoid including a piston is mounted exterior to a feed tube. A butterfly valve is within the feed tube at the inlet. A pin is within the piston, and a shaft of the butterfly valve is bent to connect to the pin such that the solenoid can drive the butterfly valve. An exhalation valve is within the feed tube at the outlet, the exhalation valve adapted to slide axially within the feed tube and incrementally cover the outlet. Upon rotation of the butterfly valve, the exhalation valve thereby slides towards the mask side, wherein upon activation of both the airflow generator and a controller circuit, pressurized air from the airflow generator continuously enters the feed tube but is converted to a single, repeatable burst or rush.
