Table 1.

Beneficial effects of the high-flow nasal cannula.

Physiological	Clinical
Reduction of anatomical dead space	Reduction of dyspnoea
Generation of a positive end-expiratory pressure	Improved oxygenation
Maintenance of a constant fraction of inspired oxygen	Improvement in patient’s comfort due to:
Reduction in work of breathing	• optimal humidification
Improvement in mucociliary clearance	• possibility of eating or talking while under treatment
	• lack of deleterious effects from the nasal/facial mask