Remote ischaemic pre-conditioning (RIPC) has been recognized as a low-cost, non-invasive intervention method by applying brief ischaemia and reperfusion on an arm or a leg. Previous studies have mainly focused on the organoprotective effects of RIPC in patients undergoing cardiac surgery. However, whether it has an organ-protecting effect is still highly debated. We aimed to determine whether intensive RIPC can prevent from negative inflammatory response and organ dysfunction as well as postoperative complications in patients undergoing cardiovascular surgery.

Inclusion Criteria:

• patients at high risk for organ dysfunctions who underwent elective cardiovascular surgery requiring cardiopulmonary bypass (CPB);
• age of 18 -80 years old, regardless of gender;
• subjects voluntarily participate in the trialand sign the informed consent;

Exclusion Criteria:

• 1) Arm fracture, skin injury or infection;
• 2) There is limb nerve injury;
• 3) Limb placement PICC, arteriovenous fistula and other devices that affect armband placement;
• 4) There are basic vascular lesions and poor blood supply at the extremities;
• 5) Limb thrombosis.