Abstract: AIM: To observe the incidence,risk factors and prevention methods of delirium after aortic arch operation.METHODS: The incidence of delirium in 143 patients who received aortic arch surgery was retrospectively analyzed.Patients were divided into two groups according to occurrence or no occurrence of postoperative delirium.Possible delirium-causing risk factors were analyzed.RESULTS: Except for early postoperative death due to cardiac and pulmonary failure in three patients,the incidence of delirium was 29.3%(41/140).Risk factors for postoperative delirium included 1) preoperative diseases such as hypertension,cerebrovascular diseases and diabetes mellitus;2) lower cerebral oxygen saturation,cardiopulmonary bypass(CPB)>200 min,minimum systolic blood pressure and duration of minimum blood pressure during operation,and 3) postoperative fever and blood transfusion volume >3 000 ml.CONCLUSION: Minimum systolic blood pressure and duration of minimum blood pressure,CPB>200 min and cerebral oxygen saturation <40% during operation are independent risk factors for the occurrence of delirium.