Incidence and Associated Factors of ST-Segment Changes in Noncardiac Surgery Under General Anesthesia.

BACKGROUND: Intraoperative cardiac complications may result from an imbalance between myocardial oxygen supply and demand or from plaque rupture. Electrocardiographic (ECG) alterations in the ST-segment observed during surgery or anesthesia can serve as indicators of myocardial ischemia. Numerous factors influence ST-segment variability. This study aimed to investigate the incidence of ST-segment changes and the factors associated with their occurrence. METHODS: This prospective observational study enrolled adult patients (aged ≥ 20 years) undergoing noncardiac surgery under general anesthesia. Intraoperative ST-segment monitoring was performed using a five-electrode system. Predisposing factors for ischemia, including hemodynamic parameters, coexisting diseases, and surgical characteristics, were evaluated. A P-value of <0.05 was considered statistically significant. RESULTS: A total of 102 patients were evaluated, with a mean age of 46.75 ± 16.30 years, comprising 46 males (45.1%). Postinduction ST-segment depression was greater than preinduction (-0.030 to - 0.055 vs. 0.010 to 0.060, respectively) (P = 0.0 01). ST-segment values were significantly more depressed in patients with underlying conditions, particularly hypertension and diabetes mellitus (P = 0.001). Also, the variations in ST-segment alteration were considerable among minor and major surgeries (P = 0.041). Overall, 20 patients (19.6%) exhibited prominent ST-segment changes (greater than 0.1 mV) during surgery; however, the changes were predominantly transient and managed successfully with initial clinical interventions (e.g., fluid administration). While postinduction blood pressure showed a significant drop, no statistical association was observed between the magnitude of blood pressure changes and the occurrence of ST-segment changes (P = 0.10). No significant relationship was identified between ST-segment changes and other evaluated factors. CONCLUSION: The intraoperative ST-segment changes occurred following anesthetic induction and are significantly correlated with predisposing factors, specifically hypertension, diabetes mellitus, and major vs. minor surgeries. Despite significant hemodynamic alterations during the procedure, a direct correlation with prominent ST-segment changes could not be statistically established. Given the transient nature of most alterations, further studies incorporating postoperative troponin measurement and long-term follow-up are warranted to clarify the clinical significance of these intraoperative findings.