Copyright © 2019 International Anesthesia Research Society. Unauthorized reproduction of this article is prohibited. XXX 2019 • Volume XXX • Number XXX www.anesthesia-analgesia.org 1 DOI: 10.1213/ANE.0000000000004155 B reech presentation during pregnancy is common and can risk complications during birth. 1 At term, the prevalence of breech presentation is about 3%–4% of pregnancies. 2 Current recommendations specify that in the case of breech presentation, a cesarean delivery is performed rather than attempted vaginal delivery due to a reduction in perinatal morbidity and mortality. 1,2 An alternative to cesarean delivery is external cephalic version in which the fetus is manually turned to the vertex position, allowing for an attempted vaginal delivery and therefore a decrease in cesarean delivery rate. 1 Relaxation of the uterus and abdom- inal muscles increases the success rate of external cephalic version. 3,4 Abdominal relaxation is often accomplished via neuraxial anesthesia, while tocolytic agents are used to pro- vide uterine relaxation. 3,4 The use of tocolytics has been found to increase the success rate of external cephalic version and decrease the cesarean delivery rate. 4 Two such tocolytic agents, nitro- glycerin and terbutaline, have been shown to increase the success rate of external cephalic version. 5,6 Only 2 studies in the literature compare these 2 agents; in neither study was neuraxial anesthesia used. 7,8 At our institution, practitioners routinely use either terbutaline or nitroglycerin in combina- tion with a neuraxial anesthetic for external cephalic ver- sion. Our hypothesis was that there would be no difference in success rate between the 2 agents. We, therefore, per- formed a retrospective study comparing the success rate of external cephalic version in parturients who received neur- axial anesthesia along with either IV nitroglycerin or subcu- taneous terbutaline. METHODS After approval from the institutional review board of the Icahn School of Medicine and a waiver of informed consent, medi- cal records of patients who underwent an attempted external cephalic version from January 1, 2007 to December 31, 2017 at The Mount Sinai Hospital in New York, New York, were reviewed. Initial cases were identifed via Current Procedural Terminology codes and then verifed by visual inspection of the medical record. Patient’s weight, gravidity, parity, amni- otic fuid index, weeks of gestation at the time of external cephalic version, type of breech, placental location, obstetri- cian, and type of anesthesia were assessed. All data were col- lected from both the electronic medical record (Epic, Verona, WI) and anesthetic records (CompuRecord; Phillips, Andover, MA). Our standard neuraxial anesthetic for external cephalic version is spinal anesthesia with 1–1.5 mL hyperbaric bupi- vacaine 0.75% with or without fentanyl. Version technique in general consists of front and back rolls depending on the position of the fetus and is limited to 3 attempts. The success rate of external cephalic version and type of delivery (vaginal delivery or cesarean delivery) were collected from the elec- tronic medical record. There were no protocols or procedures mandating the use or type of tocolytic for external cephalic version and was at the discretion of the care team. Statistics and Power Analysis All continuous variables were tested for normality using visual inspection and the Shapiro–Wilk test. Those that were determined to be nonnormal are reported as median (interquartile range) versus mean (SD) for normally distrib- uted variables. Categorical variables are represented as n (%). Comparative testing for continuous variables such as height, weight, gravidity, parity, gestational age, amniotic fuid index, and dosages of medications was performed using Mann-Whitney U test between the nitroglycerin and terbutaline groups. χ 2 tests were used to assess differences between categorical variables such as nulliparity, placental location, breech type, obstetrician performing the version, and version success rate between the nitroglycerin and External cephalic version is a technique that decreases the need for cesarean delivery in patients with breech presentation. Several techniques exist to increase the success of external cephalic version; however, there are no studies comparing different tocolytics in patients who also received neuraxial anesthesia. We, therefore, performed a review of 198 patients who pre- sented for external cephalic version and compared their success rates based on the tocolytic medication utilized. The external cephalic version success rate for patients who received ter- butaline was signifcantly higher than for those who received nitroglycerin (N [%]: 57 [65.6] ter- butaline group versus 40 [36.0] nitroglycerin group; P < .001). (Anesth Analg XXX;XXX:00–00) Comparison of Nitroglycerin and Terbutaline for External Cephalic Version in Women Who Received Neuraxial Anesthesia: A Retrospective Analysis Daniel Katz, MD,* Kyle Riley, MD,† Elizabeth Kim, BS,‡ and Yaakov Beilin, MD*§ From the *Department of Anesthesiology, Pain, and Perioperative Medicine, Icahn School of Medicine, New York, New York; †Department of Internal Medicine, Northwell Health John T. Mather Memorial Hospital, Port Jefferson, New York; ‡City University of New York School of Medicine, New York, New York; and §Department of Obstetrics, Gynecology, and Reproductive Sciences, Icahn School of Medicine, New York, New York. Accepted for publication February 26, 2019. Funding: None. The authors declare no conficts of interest. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website (www.anesthesia-analgesia.org). Reprints will not be available from the authors. Address correspondence to Daniel Katz, MD, Department of Anesthesiology, Pain, and Perioperative Medicine, Icahn School of Medicine, KCC 8th Floor, Box 1010, 1 Gustave L Levy Place, New York, NY 10029. Address e-mail to daniel.katz@mountsinai.org. Copyright © 2019 International Anesthesia Research Society E BRIEF REPORT