Evaluation of the Relationship Between Endothelial Activation and Stress Index (EASIX) and Post-Induction Hypotension in Frail Patients Undergoing Non-Cardiac Surgery: A Prospective Observational Cohort Study

Post-induction hypotension (PIH) is a common and clinically significant hemodynamic complication following general anesthesia induction. Frail patients are particularly vulnerable due to impaired vascular reactivity and endothelial dysfunction. The Endothelial Activation and Stress Index (EASIX), calculated from routine laboratory parameters (LDH, creatinine, and platelet count), may serve as a preoperative biomarker to identify patients at risk for PIH. This prospective observational cohort study aims to evaluate the association between preoperative EASIX score and the occurrence of post-induction hypotension in frail patients undergoing elective non-cardiac surgery under general anesthesia. A total of 160 patients with a Clinical Frailty Scale (CFS) score of 4 or above will be enrolled. Mean arterial pressure will be measured every 2 minutes for the first 15 minutes after induction. PIH is defined as MAP below 65 mmHg and/or a decrease of 20% or more from baseline.