///2009 Abstract Details
2009 Abstract Details2019-08-03T15:55:31-06:00

Intravenous oxytocin in elective cesarean section. A randomized, single-blind study of maternal hemodynamics and uterine tone.

Abstract Number: 171
Abstract Type: Original Research

Eduardo T Yamaguchi MD1 ; Monica MSC Cardoso MD, PhD2; Manoel CSA Ribeiro MD, PhD3; Rosana C Nascimento Biologist, PhD4; Didier Payen MD, PhD5; Marcelo LA Torres MD, PhD6

Oxytocin is routinely used in obstetrics to reduce and prevent postpartum hemorrhage after cesarean delivery. The purpose of this study was to evaluate the maternal hemodynamics and the effective uterine tone after using intravenous oxytocin at different doses and infusion rates in patients undergoing elective cesarean section.

A randomized, single-blinded trial was undertaken in 30 patients for elective cesarean section under spinal anesthesia using 15 mg 0.5% hyperbaric bupivacaine added to 40 mg morphine. Systolic blood pressure (SBP) and heart rate controls were defined as the average of three measurements of such parameters taken immediately prior to spinal anesthesia. Any occasional drop in SBP control was treated with 0.2 mg of metaraminol and considered maternal hypotension. Intravenous oxytocin was administered by infusion pump immediately after clamping of the umbilical cord using syringes with total volume of 20 mL of solution in accordance with the following scheme. Group I: 10 IU of oxytocin diluted in 18 mL of saline (total volume 20 mL) and infused at the rate of 0.33 IU/min. Group II: 10 IU of oxytocin diluted in 18 mL of saline infused at the rate of 2.67 IU/min. Group III: 80 IU of oxytocin diluted in 4 mL of saline infused at the rate of 2.67 IU/min. Uterine tone was measured by palpation by the surgeon at 5, 30 and 60 minutes after starting oxytocins infusion and then classified as satisfactory or not. Blood loss was assessed through the patients hematocrit levels collected before the anesthesia and 60 minutes after birth. All three groups were similar regarding anthropometric variables and control hemodynamic values. The incidence of nausea and vomiting was also similar in all groups. The ANOVA test was used to carry out the statistical analysis of the hemodynamic data (hypotension, hypertension, bradycardia and tachycardia) as well as the consumption of metaraminol comparing the number of episodes to total number ratio (average) before and after oxytocin infusion, and no significant statistical differences were found between these variables (p > 0.05). In addition, there was no difference between pre-op and post-op hematocrit values.

No hemodynamic alterations or any significant maternal discomfort with the oxytocin doses and rates used was observed in this study. The uterine tone was considered satisfactory in all groups at the three intervals studied and no additional uterotonic agents were needed.

SOAP 2009