Nasal Highflow (NHF) reduces PCO2 in a sheep lung model via airway wash-out

Aims: Nasal Highflow has a growing importance in clinical practice. Unfortunately there exist only few studies about effectiveness and mode of action of this new non-invasive ventilatory support device. Some authors prefer pressure increase as the mean mechanism. But there is evidence about wash-out of upper airways and resolved dead space ventilation. This results in a decrease in hypercapnia. We want to prove the hypothesis that Nasal Highflow works through a wash-out effect in small airways. Methods: We used a shep lung model in a self-constructed vacuum box. NHF was applied through a nasopharynx-model. CO2 (…