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.
EASIX is calculated as: LDH (U/L) × Creatinine (mg/dL) / Platelet count (10⁹/L), using routine preoperative laboratory values obtained within 24 hours before surgery. All patients will receive a standardized anesthesia induction protocol: midazolam 0.05 mg/kg, fentanyl 2 mcg/kg, propofol 2 mg/kg, and rocuronium 0.6 mg/kg intravenously, followed by endotracheal intubation after 2 minutes of mask ventilation. Anesthesia maintenance will consist of 2% sevoflurane and remifentanil 0.2 mcg/kg/min infusion. The primary outcome is the occurrence of PIH within the first 15 minutes after induction. Secondary outcomes include the diagnostic performance of EASIX (ROC-AUC analysis) and the interaction between frailty severity and EASIX on PIH development. Multivariable logistic regression will be performed adjusting for age, sex, ASA classification, baseline MAP, antihypertensive medication use, fasting duration, and induction agent doses.
Study Type
OBSERVATIONAL
Enrollment
160
Preoperative Endothelial Activation and Stress Index (EASIX) score calculated from routine laboratory parameters obtained within 24 hours before surgery. Formula: LDH (U/L) × Creatinine (mg/dL) / Platelet count (10⁹/L). No additional blood sampling is performed; only existing routine preoperative laboratory values are used.
Konya City Hospital
Konya, Turkey (Türkiye)
RECRUITINGIncidence of Post-Induction Hypotension
Occurrence of MAP below 65 mmHg and/or a decrease of 20% or more from baseline mean arterial pressure, measured every 2 minutes for the first 15 minutes after anesthesia induction, before surgical incision.
Time frame: Within the first 15 minutes after anesthesia induction
Diagnostic Performance of EASIX Score for Post-Induction Hypotension
Area under the receiver operating characteristic curve (ROC-AUC) of preoperative EASIX score for predicting post-induction hypotension. EASIX is calculated as: LDH (U/L) × Creatinine (mg/dL) / Platelet count (10\^9/L). ROC-AUC ranges from 0.5 (no discrimination) to 1.0 (perfect discrimination); higher values indicate better predictive performance. Optimal cut-off value will be determined by Youden index.
Time frame: Preoperative assessment within 24 hours before surgery
Interaction Between Frailty Severity and EASIX on Post-Induction Hypotension
Effect modification of Clinical Frailty Scale (CFS) score on the association between preoperative EASIX score and post-induction hypotension, evaluated by multivariable logistic regression with interaction term. CFS ranges from 1 (very fit) to 9 (terminally ill); higher scores indicate greater frailty. EASIX is a continuous score with no fixed range; higher values indicate greater endothelial stress. Results will be reported as odds ratios with 95% confidence intervals.
Time frame: Within the first 15 minutes after anesthesia induction
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