Effect of Controlled Hypotension on GFAP and Cognition in Rhinoplasty

Evaluation of the Effect of Controlled Hypotension During Elective Rhinoplasty on Serum Glial Fibrillary Acidic Protein (GFAP) and Cognitive Functions

This prospective observational study aims to evaluate the neurological safety of controlled hypotension (Mean Arterial Pressure 50-65 mmHg) during elective rhinoplasty. The investigators will assess whether this standard intraoperative hypotensive strategy causes cellular stress by measuring serum Glial Fibrillary Acidic Protein (GFAP) levels and early postoperative cognitive changes using the Montreal Cognitive Assessment (MoCA) test.

Controlled hypotension is frequently utilized in rhinoplasty to minimize bleeding and improve the surgical field. However, the potential cellular stress on the brain due to reduced cerebral perfusion is not fully understood. This study will enroll 40 ASA I-II patients undergoing elective rhinoplasty under general anesthesia with sevoflurane. Blood samples will be drawn at baseline (after anesthesia induction) and 24 hours postoperatively to measure serum GFAP levels via ELISA. Cognitive functions will be evaluated simultaneously using the MoCA test. The primary objective is to determine the change in GFAP concentrations, and the secondary objective is to evaluate its correlation with early postoperative cognitive scores.

Inclusion Criteria:

• Scheduled for elective rhinoplasty or septorhinoplasty under general anesthesia.
• ASA physical status I or II.
• Literate and willing to provide written informed consent.

Exclusion Criteria:

• History of neurological (e.g., cerebrovascular event, epilepsy) or psychiatric diseases.
• Total septal reconstruction requiring costal (rib) cartilage grafts.
• Expected surgical duration exceeding 3 hours.
• Preoperative severe cognitive impairment.
• Pregnancy or lactation.