High-flow Oxygen Therapy in Acute Respiratory Failure

Traditionally, high-flow oxygen therapy (HFOT) was defined as the delivery of a flow of oxygen higher than 6 L/min. Recently, however, a method has been described in which flows of up to 50 L/min are delivered through a nasal cannula with a heated humidifier that optimizes oxygen administration. HFOT improves oxygenation by various mechanisms, for instance by decreasing oxygen dilution, reducing respiratory dead space, and generating a continuous positive airway pressure effect. It may also have a beneficial effect on hemodynamics, exercise capacity, and comfort, especially when a nasal cannula is used. HFOT is now a viable treatment option because of the use of heated humidifiers, which allow delivery of conditioned inspiratory gases at 37°C and 100% humidity. Properly conditioned gas provides higher comfort and minimizes deterioration of nasopharyngeal structures. Various HFOT systems are currently available. It is important to use the most comfortable device for the patient in question, with the best gas conditioning.