Compare Hemodynamic Effect of Oxytocin Bolus and Infusion During Cesarean Section Under Spinal Anesthesia

The administration of Oxytocin during cesarean section under Spinal anesthesia is associated with significant hemodynamic changes, and these effects differ depending on whether the drug is given as an intravenous bolus or as a controlled infusion. Oxytocin causes vasodilation and decreases systemic vascular resistance, which can lead to hypotension, reflex tachycardia, and occasionally nausea or flushing-effects that are often exaggerated under spinal anesthesia due to pre-existing sympathetic blockade. When given as a rapid IV bolus (e.g., 5-10 IU), there is a sudden drop in blood pressure and a marked increase in heart rate, sometimes accompanied by transient myocardial ischemia in susceptible patients. In contrast, administering oxytocin as a slow infusion (e.g., 10-40 IU diluted in IV fluids over time) results in more gradual hemodynamic changes, with better stability of blood pressure and heart rate. Comparative studies have consistently shown that infusion regimens are associated with fewer adverse cardiovascular effects while still providing adequate uterine contraction. Therefore, current clinical practice favors low-dose slow bolus followed by infusion, or infusion alone, to minimize hemodynamic instability while effectively preventing postpartum hemorrhage.