High-flow nasal oxygen (HFNO) is an advanced oxygen delivery system used in critically ill patients who require higher levels of oxygen support than conventional nasal cannula or face masks can provide. HFNO delivers heated, humidified oxygen at high flow rates through specialized nasal prongs, improving oxygenation and reducing work of breathing while maintaining patient comfort.

HFNO is commonly used in patients with acute hypoxemic respiratory failure, pneumonia, early acute respiratory distress syndrome, post-extubation support, and during escalation or de-escalation of respiratory therapy. It is also beneficial in patients who cannot tolerate tight-fitting NIV masks or who require prolonged oxygen therapy.

The system delivers oxygen at flow rates of up to 60 liters per minute, with precise control over oxygen concentration. Heating and humidification prevent airway dryness, improve secretion clearance, and enhance patient tolerance. The high flow also generates a low level of positive airway pressure, helping keep airways open and reducing breathing effort.

Patients on HFNO can eat, speak, and remain relatively mobile, making it a patient-friendly option. Continuous monitoring of oxygen saturation, respiratory rate, and clinical response is essential. HFNO may prevent the need for intubation in selected patients, but delayed escalation must be avoided if respiratory failure progresses.

HFNO has become a vital component of modern ICU respiratory care, bridging the gap between conventional oxygen therapy and mechanical ventilation.