A Trial Comparing Combined Spinal- Epidural Dosing Strategies for External Cephalic Version

Overview

We plan to conduct a prospective, single blinded, randomized clinical trial to assess the impact of combined spinal-epidural dosing on the success rate of, and patient satisfaction during, external version for breech fetal position and the incidence of vaginal vs. Cesarean delivery. The research aim of this project is to determine the ideal neuraxial dosing strategy to maximize success of external cephalic version (ECV). The research questions, does a combined spinal-epidural (CSE) of a higher dose result in greater success in converting a breech presentation to vertex during external cephalic version (ECV). The hypotheses of this project is that CSE at higher dose will result in greater ECV success than analgesic dosing. The research significance:Increasing the success and comfort of ECV for fetal malpresentation may help decrease the cesarean section rate.

At term 2 to 3% of singleton pregnancies are in breech presentation. Many of these deliveries are managed by cesarean delivery due to higher neonatal morbidity associated with vaginal breech delivery. However, cesarean delivery, the safer option for the baby, is associated with a higher incidence of maternal complications for both the current and subsequent pregnancies. External cephalic version (ECV) is a procedure commonly used to attempt to manually rotate the fetus into vertex position. This facilitates vaginal delivery and thus avoids higher maternal and/or neonatal complications. (Hofmeyr Cochrane Review) Obstetricians generally perform versions after 36 weeks gestational age with a reportable success rate of 50-80%, depending on several factors, including patient characteristics. (Fortunato, Zhang, ACOG 1997 ECV) The most common technique involves external manipulation of the fetal position preceded by pharmacologic uterine relaxation. Until recently, pain relief was generally provided in the form of intravenous opioids such as fentanyl. A more efficacious form of analgesia is the use of neuraxial opioids and local anesthetics (neuraxial analgesia), a technique commonly used for labor and delivery analgesia. Two non-randomized studies of neuraxial analgesia compared to systemic analgesia found improved success of external cephalic version in the neuraxial analgesia groups.(Carlan, Birnbach) Three randomized trials have conflicting results: 2 demonstrate an increase in success, one shows no difference. (Dugoff, Schorr, Mancuso) None of these studies have blinded the obstetrician performing the version. In 2010, Lavoie and colleagues completed a meta-analysis looking at ECV performed under analgesic and anesthetic neuraxial doses. The analgesic dose included spinal bupivacaine and epidural dosing. The anesthestic groups gave higher doses of spinal or epidural bupivacaine. This meta-analysis suggested that those patients who had received an anesthetic dose of had more successful ECV. All published studies examining pain outcomes have demonstrated that neuraxial analgesia results in greater patient comfort during this procedure. The American College of Obstetricians and Gynecologists (ACOG) has stated, "Currently there is not enough evidence to make a recommendation favoring or opposing anesthesia during ECV (external cephalic version) attempts."