///2019 Abstract Details
2019 Abstract Details2019-07-13T07:45:15-05:00

Institution of Low-dose Oxytocin Protocol for Cesarean Delivery After Labor Arrest.

Abstract Number: F3H-449
Abstract Type: Original Research

Ghislaine C Echevarria MD MS1 ; Ghislaine C Echevarria MD MS2; Andrew Agoliati MD3; Christina Dgheim DO4; Jerome Lax MD5; Gilbert J Grant MD6

Introduction: Oxytocin administration augments myometrial contraction and decreases blood loss, but may also produce vasodilatation, hypotension and tachycardia [1]. Optimal oxytocin dosing should reduce blood loss while minimizing untoward systemic effects. After publication of the “Rule of Threes” [2], we decided to incorporate a lower dose oxytocin protocol into our practice. Upon delivery of the placenta, we administer 3 IU of oxytocin i.v. and after 3 min the obstetrician assesses uterine tone. If the tone is not adequate, the cycle is repeated two more times, if necessary, up to a total of 9 IU. If uterine tone remains inadequate, we administer second-line uterotonics. Postoperatively, an infusion of oxytocin at 2.5 IU/hour is started in the PACU, and continued for a total of 8 hours. Previously, our practice was to administer 40 IU of oxytocin i.v. during the interval from delivery of the baby to departure from the OR. This study evaluated the effect of this new low-dose oxytocin protocol on quantified blood loss (QBL) in unplanned cesarean delivery for labor arrest.

Methods: We analyzed the electronic medical records of cesarean delivery after labor arrest from November 2015 to December 2018. The months of November and December 2017 were excluded, as this was the interval when the new low-dose oxytocin protocol was being introduced. The “old” protocol was in effect through October 2017 and the new protocol was in effect from January 2018 through December 2018. For each encounter we extracted demographic data, obstetrical information (use of oxytocin either for induction and/or augmentation of labor, birth weight, gestational age, parity), and QBL. Propensity scoring (PS) methods (matching and inverse weighting) were used to compare the pre (n=917) and post intervention period (n=678), after controlling for selection bias.

Results: Based on the PS matched sample, the QBL during the new low-dose protocol was not statistically different than the “old” protocol (b coefficient [b] = 14 mL, 95% confidence interval [CI], -71 to 100, p=0.75). Similar results were obtained after PS weighting, using the average treatment effect on the treated [ATT] (b: -18 mL; 95%CI, -95 to 60, p=0.66).

Discussion: In cesarean deliveries for labor arrest, the implementation of a new low-dose oxytocin protocol was not associated with a decrease in QBL, compared to our “old” dosing regimen. We used QBL as a surrogate for uterine tone. The oxytocin dose needed to achieve adequate uterine tone is greater in patients who have been exposed to oxytocin during labor. This may be due to desensitization of uterine oxytocin receptors [3], and may explain why the low-dose oxytocin used in this population was insufficient to induce the necessary increase in uterine tone.

References:

1. J Anaesthesiol Clin Pharmacol. 2013;29(1):32-5.

2. Anesthesiology 2015;123(1):92-100.

3. Curr Pion Anaesthesiol. 2011 Jun;24(3):255-61.

SOAP 2019