Postoperative delirium (POD) is one of the most frequent neurological complications in elderly patients and is closely associated with longer ICU stay and hospitalization, deterioration of long-term neurocognitive function, and increased mortality. The incidence of POD is significantly higher in elderly patients undergoing cardiac surgery than in other populations. Therefore, the prevention of POD is an important clinical problem to be solved urgently. In this study, we intend to observe the effect of RIPC on the prevention and treatment of POD in patients undergoing cardiac surgery through a prospective randomized controlled trial.

Inclusion Criteria:

• patients undergoing elective cardiac surgery;
• age ≥ 18 yr;
• any sex;
• American Society of Anesthesiologists (ASA) class ≥II class;
• New York Heart Association (NYHA) ≥II class.

Exclusion Criteria:

• emergency surgery;
• a history of cardiovascular surgery;
• peripheral vascular disease affecting the upper limbs;
• acute myocardial infarction (MI) up to 14 days before surgery;
• a history of severe injuries and operations within 3 months before cardiac surgery;
• a history of cancer and chronic autoimmune diseases.