The Effects of Flow Settings During High Flow Nasal Cannula for Adult Hypoxemia Patients

High flow nasal cannula (HFNC) delivers oxygen at a flow which exceeds the patient's inspiratory flow demand in order to improve oxygenation. Numerous randomized control trials and meta-analyses have shown that HFNC improves oxygenation and helps avoid intubation in hypoxemic patients, as well as reduce work of breathing, improve ventilation, and decrease hypercapnia in COPD patients. Flow settings play a critical role when using HFNC, as increased flow can reduce inspiratory effort, improve ventilation, and dynamic lung compliance. However, flow rates used in many studies vary widely. The clinical effects of different HFNC flow setting, specifically to match or over than a patients' own inspiratory flow, is still unknown.