Figure 2.

EDS mechanism. The EDS has a flexible mouthpiece and a nosepiece. The sealing nosepiece is shaped to transfer pressure from the mouth, to avoid compression of soft tissue in a way that could obstruct air flow, and to “stent” the nasal valve, particularly superiorly. Exhalation through the EDS (1) creates an airtight seal of the soft palate, isolating the nose from the mouth and lungs; (2) transfers proportional air pressure into the nose; and (3) helps “float” medication around obstructions to high/deep sites in the nasal labyrinth, such as the OMC. The transferred intranasal pressure is proportional, across various exhalation forces, to oral pressure, counterbalancing pressure on the soft palate. This assures a patient communication behind the nasal septum and allows air to escape through the opposite nostril. “Positive-pressure” expands passages narrowed by inflammation (vs. negative pressure delivery, “sniffing”). Use is simple and quick. A patient inserts the nosepiece into one nostril and starts blowing through the mouthpiece. This elevates and seals the soft palate, as with inflating a balloon, separating the oral and nasal cavities. The patient completes use by pressing the bottle to actuate. This causes a coordination-reducing valve to release the exhaled breath concurrently with aerosol spray in a “burst” of naturally humidified air. Reproduced with permission from [84], John Wiley & Sons, Inc., 2018.