Electrocardiographic Changes in Elective Cesarean Delivery after Oxytocin Injection: Regional Anesthesia versus General Anesthesia

Abstract

Background: There is evidence that electrocardiographic (ECG) changes occur during elective cesarean section in parturients. These changes, mostly in the form of ST-segment depression, have been noted in either regional anesthesia or general anesthesia. We performed this study to compare hemodynamic variables and electrocardiographic changes suggestive of myocardial ischemia following administration of oxytocin in elective cesarean delivery between regional and general anesthesia methods.
Methods: In this double-blinded randomized clinical trial, 130 parturients were randomly divided into two groups of general anesthesia (65 cases) and spinal anesthesia (65 cases). After delivery of the baby and placenta, firstly a bolus of 5 units of oxytocin was injected, and then 30 units of oxytocin was infused over 30 minutes in both groups. Hemodynamic variables including heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were studied. ECG recording was done twice (1 hour and 24 hour) after the operation. For those who demonstrated ECG changes, serum troponin I level was measured.
Results: The ECG changes suggestive of ischemia was higher in general anesthesia group (36.9%, 24 cases) compared to spinal anesthesia group (24.6%, 16 cases), but it was not statistically significant (P= 0.12). Troponin I levels checked for patients with ECG changes were all within normal limits.
Conclusion: Although ST depression on ECG was more prevalent in parturients who underwent cesarean section under general anesthesia compared to spinal anesthesia, the difference was not statistically significant. None of the cases demonstrated myocardial injury based on Troponin I measurements.