Effects of Two Different Mean Arterial Pressure Targets During Controlled Hypotension on Renal Injury Assessed by NGAL Levels in Patients Undergoing Septoplasty

Controlled hypotension is frequently used during septoplasty to reduce intraoperative bleeding and improve surgical field visibility. However, excessive reductions in mean arterial pressure (MAP) may impair renal perfusion and potentially contribute to postoperative kidney injury. Traditional markers of renal dysfunction, such as serum creatinine, may not detect early renal injury. Neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a sensitive biomarker for the early detection of acute kidney injury.

This prospective randomized study was designed to evaluate the effects of two different MAP target ranges during controlled hypotension on renal injury in patients undergoing elective septoplasty under general anesthesia. Patients were randomly assigned to one of two groups: a lower MAP target group (50-57 mmHg) and a higher MAP target group (58-65 mmHg). Controlled hypotension was achieved according to standard anesthetic practice throughout surgery.

Renal injury was assessed by measuring plasma NGAL concentrations preoperatively and at predetermined postoperative time points. Additional renal function parameters, including serum creatinine levels, urine output, and acute kidney injury classifications, were evaluated. Intraoperative hemodynamic variables and renal regional oxygen saturation values were also recorded.

The primary objective of the study was to determine whether different levels of controlled hypotension influence early renal injury as assessed by NGAL measurements. Secondary objectives included evaluation of conventional renal function parameters, renal tissue oxygenation, and perioperative hemodynamic outcomes.