Supplemental Video 2

<p><strong>Carbon dioxide (CO</strong>_{<strong>2</strong>}<strong>) clearance in an upper-airway model during asymmetrical nasal high flow.</strong></p> <p> The asymmetrical interface generated reverse flow and across the choana, which led to unidirectional purging of expired gas from the upper airways.  A slow-motion playback with velocity vectors demonstrates purging of CO₂ via the less occluded nare during expiration.</p>