To investigate the morbidity of intestinal injury after open surgery and observe the effect of comprehensive intestinal protection strategy on postoperative intestinal complications in patients undergoing laparotomy with general anesthesia.

Perioperative intestinal injury is one of the common tissues and organs injury in surgical practice. However, there is a lack of effective means of prevention and treatment.The investigators previously found that ischemic preconditioning, IPC, and dexmedetomidine has protective effects on intestinal mucosal injury.

However, the combined effect of various factors has not been clinically validated. To explore the effect of comprehensive intestinal protection strategy on postoperative intestinal complications in patients undergoing laparotomy with general anesthesia,the investigators select the patients undergoing open surgery under general anesthesia as the study subjects and the concentration of intestinal fatty acid binding protein (I-FABP) as well as the incidence of digestive system complications in one week after operation are the main observation indexes.

Inclusion Criteria:

• Aged between 18 and 70 years;
• Elective abdominal surgery under general anesthesia, operation time > 2h;
• ASA Ⅰ ~ Ⅲ;
• Patient informed and consent to accept the test.

Exclusion Criteria:

• persons under the age of 18 or over 70 years old;
• pregnant or lactating women;
• combined with lung, liver, kidney, cardiovascular and hematopoietic system disease and other serious primary disease;
• preoperative Hb <7g / l;
• oral sulfa drugs or nicorandil antihypertensive drugs;
• lower extremity amputees;
• with peripheral vascular disease;
• patients with mental illness or severe neurosis;
• can not express the subjective symptoms;
• nearly 3 months to participate in other drug clinical trials;
• within 3 months of receiving other surgical treatment.