Pulmonary dysfunction after cardiac surgery with CPB remains to be a problem complicating the postoperative course of the patients. The investigators hypothesized that RIPCcom, combined intervention of remote ischemic preconditioning and remote ischemic postconditioning, would confer beneficial influence on inflammatory response and resultant postoperative pulmonary dysfunction after CPB in patients undergoing complex valvular heart surgery who are at increased risk of postoperative pulmonary dysfunction.The aim of this study was to evaluate the lung-protective effect of combined remote ischemic pre- and post-conditioning in patients undergoing complex valvular heart surgery.

Inclusion Criteria:

• patients undergoing valvular heart surgery.
• Age: 20~80.

Exclusion Criteria:

• Emergency operation.
• patients with peripheral vascular disease.
• Patients with a known history or clinical evidence of chronic obstructive pulmonary disease.
• Patients with hepatic or renal dysfunction
• Patients with acute myocardial infarction within 1 week before surgery