An interrupted aortic arch is a rare, duct-dependent lesion, where the perfusion for the lower limbs and sometimes the left arm is provided from a R → L shunt via the duct. Clinical signs depend on the location of the interruption, with cyanosis, low blood pressure and weak pulses in the lower limbs. Anaesthetic management includes a Prostin infusion to keep the duct open and to keep the pulmonary blood pressure high with a low FiO2 and mild hypoventilation, to keep an adequate perfusion pressure for the kidneys and gut.