Innominate artery dissection with presentation of sudden right frontal desaturation detected by cerebral oximetry in complicated thoracic aortic aneurysm repair surgery: a case report.

Cerebral oximetry is a noninvasive bedside monitor for cerebral oxygen saturation (rSO2). A patient with a thoracic aneurysm underwent combined surgical and endovascular repair. A sudden decrease in right rSO2 led to the finding of acute innominate artery dissection. Immediate repair was instituted. Sudden asymmetry of rSO2 may be a warning sign of underlying pathology.