Perioperative organ injuriy remain an important threat to patients undergoing major surgeries. Intraoperative hypotension is associated with an increase in postoperative morbidity and mortality. Whereas individualized intraoperative blood pressure management is likely to decrease the incidence of postoperative organ injury when compared with standard blood pressure management strategy. Dexmedetomidine, a highly selective alpha2 adrenergic agonist, has been shown to provide organ protective effects. This study aims to investigate the impact of intraoperative goal-directed blood pressure management and dexmedetomidine infusion on incidence of postoperative organ injury in high-risk patients undergoing major surgery.

The number of patients undergoing surgeries is increasing worldwide. However, some patients develop complications or even die after surgery. Perioperative organ injury is the leading cause of the unfavorable outcomes.

Hypotension is not uncommon during major surgery and is highly responsible for the inadequate perfusion and organ injury. A recent study showed that individualized blood pressure management decreases the incidence of postoperative organ injury when compared with standard blood pressure management strategy.

Dexmedetomidine is a highly selective alpha2 adrenergic agonist. Previous studies showed that dexmedetomidine provides organ protection in various conditions. In a recent meta-analysis, perioperative dexmedetomidine reduceds the occurrence of postoperative delirium. However, whether it can reduce postoperative complications remains inconclusive.

This study aims to investigate the impact of intraoperative goal-directed blood pressure management and dexmedetomidine infusion on the incidence of postoperative organ injury in high-risk patients undergoing major abdominal surgery.

Inclusion Criteria:

• Age 50 years or older;
• Scheduled to undergo abdominal surgery under general anesthesia with an expected duration of 2 hours or longer;
• With a preoperative acute kidney injury risk index of class III or higher (meet 4 or more of the following factors: age ≥56 years, male sex, active congestive heart failure, ascites, hypertension, emergency surgery, intraperitoneal surgery, mild or moderate renal insuffificiency, diabetes mellitus requiring oral or insulin therapy).

Exclusion Criteria:

• Severe uncontrolled hypertension (SBP>180 mmHg or diastolic blood pressure >110 mmHg);
• Acute or decompensated heart failure, acute coronary syndrome, or stroke within 1 month;
• Severe bradycardia (heart rate < 50 bpm), sick sinus syndrome, second-degree or higher atrioventricular block without pacemaker, atrial fibrillation, or frequent premature beats;
• Severe hepatic dysfunction (Child-Pugh C) or chronic kidney disease (glomerular filtration rate <30 ml/min/1.73 m2 or dependent on renal replacement therapy) ;
• Pregnant;
• Receiving dexmedetomidine or norepinephrine infusion before surgery;
• Do not provide written informed consent.

For dexmedetomidine infusion, all the participants, care providers, investigators, outcomes assessors are masked. For blood pressure management, care providers, namely anesthesiologists, are not masked.