Normally air moves in and out of tracheostomy tubes (trachs) below the level of the vocal cords rendering a patient aphonic. By using a Passy Muir Valve (PMV), otherwise known as a “speaking valve”, airflow is redirected through the vocal cords during expiration – our normal mechanism of phonation. This is because the valve permits inspiration but not expiration through its cap. The only place air can exit is by passing through the larynx (or if enough pressure builds up in the airway… popping off the valve!)
With a PMV, we also re-establish more normal physiology and improve things like oxygenation (closed system permits positive end-expiratory pressure), infection control (no need for finger occlusion of trach to phonate), and olfaction (airflow through the nasal passage). Just make sure to DEFLATE THE CUFF before placing on the PMV.