This is a prospective, randomized control trial comparing norepinephrine versus phenylephrine for vasopressor support in patients undergoing elective spinal fusion surgery.

There is limited evidence on the difference in postoperative outcomes between the choices of vasopressors used to treat intraoperative hypotension (IOH) in patients undergoing non-cardiac surgery under general anesthesia. A recent pilot feasibility trial comparing norepinephrine and phenylephrine for first-line intravenous infusion of vasopressor during general anesthesia and major non-cardiac surgery was unable to show any difference in postoperative outcomes. Although the study demonstrated safety and feasibility, it was not powered to detect differences in postoperative outcomes. The impact of vasopressors on postoperative outcomes in patients undergoing complex spinal surgery in the prone position is even scarcer. While it has been demonstrated that the use of intra-operative vasopressor infusion is safe and well tolerated, without any adverse renal outcomes, it is unclear if the choice of vasopressor makes any difference. While animal studies have shown that norepinephrine may provide greater spinal cord protection than phenylephrine, clinical studies in humans are lacking. We aim to fill this gap in knowledge by carrying out a prospective, randomized control trial to evaluate differential outcomes related to the choice of norepinephrine versus phenylephrine as the preferential vasopressor in patients undergoing elective spinal fusion surgery in the prone position.

Inclusion Criteria:

-Patients > 18 years undergoing elective, prone, spinal fusion surgery

Exclusion Criteria:

• Age < 18 years
• Emergency surgery
• Outpatient surgery
• Pregnancy
• End-stage renal disease requiring dialysis
• Diagnosed myocardial ischemia and/or cardiac revascularization within the past month