514: The effect of a postpartum physiologic oxytocin protocol on blood loss

Abstract

Oxytocin is widely used to prevent excessive blood loss postpartum. Previous studies have found that oxytocin bolus can cause hypotension and that physiologic doses of oxytocin are much lower than previously thought. The objective of this study was to determine the effect of a physiologic postpartum oxytocin protocol on postpartum blood loss as compared to oxytocin bolus. A retrospective cohort study of women delivered at Stony Brook University Hospital between March 2014 and March 2016 was conducted. In March 2015 the postpartum oxytocin protocol changed from a bolus of 40U in 1L (4U/min) to oxytocin delivered via a pump. Both protocols started after delivery of the placenta and were administered after both vaginal and cesarean births. In the study group the oxytocin was started at 0.3U/min and could be increased to 0.6U/min if uterine atony occurred. We excluded women with multiple gestations, preterm delivery, unknown gestational age, or without post-partum hematocrit value. Demographics and delivery data was collected. The primary outcome was average change in hematocrit between admission and post-partum. Secondary outcomes were number of blood transfusions and use of uterotonics. A total of 2005 records were included. Demographic and obstetric characteristics were similar between groups.There was a significant decrease in average change in hematocrit (5.2±4.8 vs. 4.6±5.1, p=0.009)with the new protocol. However, there was no significant difference in the percent of women requiring additional uterotonics (8.9% vs. 8.4%, p=0.695) or transfusion (2.4% vs. 1.5%, p=0.178) between groups. A significant decrease in blood loss and no change in uterotonics and transfusion was seen after implementation of the new protocol. Our data suggests that a physiologic dose of oxytocin may be superior to a bolus.