We report the case of a 27-year-old severe head trauma patient who developed an erosion of the brachiocephalic artery, 19 days after the insertion of a tracheal cannula. Emergency treatment included overinflation of the tracheostomy cuff and surgery via sternotomy, with occlusion of the tracheostomy and the tracheo-arterial fistula and reimplantation of the brachiocephalic artery via a vascular prosthesis. This life-threatening complication is due to close anatomic relationships between the trachea and the brachiocephalic artery. In our case, the tip of the cannula eroded the anterior trachea wall resulting in a tracheo-arterial fistula with massive haemorrhage. Warning symptoms such as pulsations of the cannula and aspiration of blood must be recognised without delay and followed by an adequate pre-established management.