Nasal high flow (NHF) cannulae are used to deliver heated and humidified air to patients at steady flows ranging from 5-50 l/min.In this study, the flow velocities in the nasal cavity across the complete respiratory cycle during natural breathing and with NHF flow have been mapped in-vitro using time resolved stereoscopic particle image velocimetry (SPIV). 丹迪粒子圖像測速儀 Dantec PIV