While it's possible that there is a small pneumothorax present it's the least likely of the three alternatives given the clinical findings of bilateral air entry and equal percussion note.

Still, despite your dodgy diagnostic skills you realise that there is no evidence of a tension pneumothorax or other chest condition requiring immediate intervention. His respiratory rate is rising, and even you know that the increased resistance to flow caused by the tracheal tube will significantly impair ventilation in children when they are breathing spontaneously.

You get Julian to connect the tube to a ventilator before moving on to your circulatory assessment.