Effect of Carbetocin on Uterine Tone during Cesarean Section: A Comparison between Subarachnoid Block and General Anesthesia

BACKGROUND: Postpartum hemorrhage remains a challenge in obstetric practice in developing climes and contributes immensely to the horrendous figures of maternal mortality worldwide. AIM: The aim was to compare the effect of intravenous (IV) carbetocin on uterine tone under different anesthetic techniques for elective cesarean section. METHODS: Four hundred and seventy-eight consecutive women scheduled for elective cesarean section were recruited into two groups by convenience. While 445 parturients received subarachnoid block (SAB), 33 had general anesthesia (GA). At delivery, IV carbetocin was administered. The uterine tone was assessed manually and blood loss from intraoperative period to the 24(th) h was determined. Other variables such as hemodynamic profiles and Apgar scores were determined and recorded. RESULTS: The bio-characteristics between the two groups were essentially the same in terms of age, weight, height, body mass index, preoperative hemoglobin, and gestational age. While the response to the administered carbetocin was slower in the GA group, there was no need for additional dose. The mean estimated intraoperative blood loss under SAB was 250.44 ± 50.59 ml and that under GA was 470.89 ± 35.70 ml, P = 0.000000. The ephedrine consumption was 6.25 ± 2.05 mg in the SAB group while it was 11.25 ± 2.49 mg, P = 0.000000. There was no further maternal blood loss observed after the intraoperative period until the end of 24-h period. The hemodynamic profiles were significantly different in terms of mean systolic blood pressure, mean diastolic blood pressure, and mean arterial blood pressure, P = 0.006, P = 0.002, and P = 0.003, respectively. However, the difference in the mean heart rate was not statistically significant, P = 0.304. While the Apgar scores between groups were not statistically significant, the mean umbilical pH was 7.34 ± 0.09 in the SAB group, it was 7.35 ± 0.02 in the GA group, P = 0.071. CONCLUSION: Intraoperative maternal blood loss was more among the parturients who received GA than subarachnoid blood. This could probably be due to the effect of the halogenated vapor used for the GA on the uterine tone. There was no further blood loss after the intraoperative period. The hemodynamic profile was better under SAB as evidenced by the total ephedrine consumption.