Respiratory support in paediatric emergency settings ranges from oxygen delivery with subnasal oxygen to invasive mechanical ventilation. Recent data suggest that oxygen can cause reperfusion injuries and should be delivered with caution within well-defined clinical target ranges. Most mild to moderate respiratory distress conditions with an oxygen requirement may benefit from early use of continuous positive airway pressure. High-flow nasal cannula therapy (HFNC) is an emerging alternative way to support the inspiratory effort combined with oxygen delivery and positive expiratory pressures without the need of complicated equipment or good compliance from the child. Besides a positive pressure support effect, HFNC therapy reduces the physiological dead space with improved CO2 clearance. A decrease in heart and respiratory rate within the first few hours after initiation of HFNC therapy is likely to identify responders of the treatment. The use of non-invasive ventilation such as continuous positive airway pressure or the use of bi-level positive airway pressure ventilation in emergency departments has increased, and it has been recognised that continuous positive airway pressure support for older children with asthma is particularly efficient.