Hypoxemia is a common complication after aortic surgery. As this complication has an adverse
effect on the postoperative course of the patient, early treatment is important; however, the
mechanism of hypoxemia after surgery for acute aortic dissection remains unclear. Recently,
the investigators found that inhaled Nitric Oxide can improve the oxygenation in some of
these patients. The investigators are trying to evaluate the effectiveness and safety of
inhaled Nitric Oxide in patients with refractory hypoxemia after aortic surgery.