No air leak on PPV does not exclude tracheobronchial injury after blunt chest trauma.

Tracheobronchial injuries are commonly associated with persistent air leak with pneumothoraces especially when on positive pressure ventilation (PPV). Injuries with absence of these features together with collapse of the lung and consequent low arterial oxygen tension while on PPV are less well recognised. We present a patient with traumatic aortic dissection and preoperatively undiagnosed complete transaction of the left main bronchus following blunt chest trauma. He had no persistent air leak with lower lung lobe collapse despite undergoing PPV and had low arterial oxygen tension which failed to respond to appropriate oxygen therapy.