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

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.

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.

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.

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.