Is 5 IU bolus of oxytocin as effective as 10 IU bolus for control of bleeding during cesarean section under spinal anesthesia?

Abstract

Aim and Objectives: We sought to compare the hemodynamic effects of 5 international unit (IU) and 10 IU of intravenous (IV) boluses of oxytocin and their efficacy in reducing blood loss during cesarean section and also to determine the incidence of postoperative nausea and vomiting (PONV) and postdural puncture headache (PDPH). Patients and Methods: One hundred and ten parturients of American Society of Anesthesiologists' I and II scheduled for cesarean section under spinal anesthesia were randomized into two groups. Group A (n = 55) received 5 IU IV bolus of oxytocin and Group B (n = 55) received 10 IU IV bolus of oxytocin after delivery. Ten milliliters per kilogram of 0.9% saline was administered to both groups as volume preload. Subarachnoid block was performed with size 24G spinal needles at L2/L3 or L3/L4 intervertebral space with the patients in sitting position. Two milliliters of 0.5% heavy bupivacaine was administered slowly intrathecally. Following delivery of the baby, IV boluses of 5 IU (Group A) or 10 IU (Group B) of oxytocin were administered slowly, and recording of heart rate, systolic, diastolic, and mean arterial blood pressure was done every minute for 5 min after bolus injection. IV infusion of 30 IU of oxytocin in 500 ml of 0.9% saline (60 mU/ml) at a rate of 125 ml/h was continued in both groups till the end of surgery. Estimated blood loss (EBL) was assessed by visual estimation. Patients were monitored continuously until 24 h after surgery to evaluate PDPH and PONV. Results: There were no statistically significant differences in the EBL between the two groups. There was no significant rise in heart rate and no significant decrease in mean arterial blood pressure in Group A compared to Group B. The incidence of PDPH and PONV was also comparable in both groups. Conclusion: Five IU of IV bolus of oxytocin is as effective as 10 IU of IV bolus in reducing blood loss during cesarean section.