Nasal Oxygen Delivery Devices Nasal cannula can be used to deliver supplemental O2. Conventional nasal cannula are commonly used deliver low flow rates & moderate FiO2. High flow nasal cannula (HFNC) delivers higher flow rates achieving a higher FiO2 with greater patient comfort. In hypoxemic respiratory failure use of HFNC is associated with a lower rate of requiring intubation & lower ICU mortality compared to CNC or NIPPV. HFNC can prevent reintubation after thoracic and cardiac surgeries. Extubation to HFNC is also associated with lower rates of re-intubation. Physiology of Heated High Flow Nasal Cannula • Higher flow washes out CO2 from anatomical dead space in the nasopharynx • Higher flow overcomes resistance against expiratory flow and creates a small positive nasopharyngeal pressure (approximatelv 0.7 cm H2O of PEEP for every 10 lpm of flow) • Patients in respiratory distress generate high flows and will entrain ambient air with conventional nasal cannula. HFNC can match demand so FiO2 remains relatively constant • Warm humidified gas preserves mucociliary function & is more comfortable for patients - Nick Mark MD @nickmmark #Nasal #Oxygen #Delivery #Devices #management #pulmonary #criticalcare
