Comparison of the Mean Minimum Dose of Bolus Oxytocin for Proper Uterine Contraction during Cesarean Section.

Background: Cesarean section is the most common midwifery operation. The aim of this study is to determine the mean minimum dose of bolus oxytocin for proper uterine contraction during cesarean section.

Methods: Patients were divided into two groups: elective cesarean section (n=41) and cesarean section due to difficulty in labor (n=42 patients). Patients underwent spinal anesthesia and oxytocin infusion was begun at 30 drops per minute (20 units of oxytocin per 1000 cc serum), and was also administered as a half-dose in cc to achieve effective contraction of the uterus. Meanwhile, the information of patients including systolic and diastolic blood pressure (SBP and DBP), heart rate and amount of bleeding during the operation was recorded in a questionnaire.

Results: In the elective cesarean section group, the average SBP was about 117.10mmHg, average DBP 70.50 mmHg, the amount of bleeding during surgery was 623.63mL, and heart rate was 88.88bpm. In the cesarean section group due to difficulty in labor progress, SBP was 113.5 mmHg, DBP 62.69 mmHg, and bleeding was 573.81mL. In addition, 9 patients in the elective group and 3 patients in the lack of progress group, did not require bolus oxytocin. In the lack of a progress group, 8 patients needed more than 5 doses of oxytocin. In addition, about 10 (12%) of all patients had no side effects, and hypotension.

Conclusion: Given that, the minimum effective dose of oxytocin in the elective cesarean section was 1IU, and in those in labor progress was 1-1.5IU, less oxytocin administration represents lesser side effects. It is recommended that patients who are candidates of cesarean section should be administered 1.5IU of oxytocin in the form of bolus.