Tissue Perfusion

The purpose of this research is to compare two commonly used medications, phenylephrine and norepinephrine, that are used to treat low blood pressure during complex spine surgery. The goal is to determine whether one medication better maintains blood flow to the body's organs during surgery and whether it leads to better recovery and fewer complications after surgery.

We will perform this single-center pilot trial to determine if the intraoperative urethral perfusion index is higher in patients assigned to maintaining postinduction baseline urethral perfusion index than in patients assigned to routine care (with blinded urethral perfusion index monitoring). As pre-planned substudies, we will also assess the agreement between a) urethral perfusion index-derived pulse rate and heart rate measured with an electrocardiogram and b) between the urethral perfusion index and the peripheral perfusion index.