///2015 Abstract Details
2015 Abstract Details2019-08-02T16:54:43-06:00

Carbetocin at Elective Cesarean Delivery: A Non-Inferiority Study between 20 and 100 mcg

Abstract Number: S-69
Abstract Type: Original Research

Samar Tabl MD PhD1 ; Mrinalini Balki MD2; Kristi Downey MSc3; Dan Farine MD4; Gareth Seaward MD MSc5; Jose Carvalho MD PhD6

Introduction: Carbetocin is recommended by the Society of Obstetricians and Gynaecologists of Canada as the uterotonic of choice to prevent postpartum hemorrhage (PPH) post elective cesarean delivery (1). The recommended intravenous dose by the manufacturer is 100 mcg; however, 3 previous studies have shown that smaller doses may be as effective (2,3,4), and that the ED 90 could be as low as 14.8mcg (95%CI 13.7 to 15.8) (4). The purpose of this study was to compare the efficacy of 20mcg and 100mcg of carbetocin.

Methods: With institutional REB approval and informed consent of each participant, this study was conducted as a randomized double-blind, non- inferiority study. We included women undergoing elective cesarean delivery under spinal anesthesia, who had no condition predisposing to PPH. They were randomized into two groups to receive either 20 mcg or 100 mcg of carbetocin intravenously upon delivery of the anterior shoulder of the baby. Uterine tone was assessed by the obstetrician at 2 and 5 minutes after carbetocin administration, according to a numerical verbal scale 0 to 10, where 0=atonic uterus and 10=firm uterus. If uterine tone was considered unsatisfactory by the obstetrician and additional uterotonic was deemed necessary, this was promptly administered according to usual practice at our hospital (oxytocin and/or ergot and/or carboprost). The primary outcome was the uterine tone (scale 0-10) at 2 minutes after carbetocin administration. Sample size was calculated at 102 subjects.

Results: Recruitment is underway and 40 cases have been completed until the preparation of this abstract. Overall, the uterine tone (mean±SD) was 7.6±1.7 and 8.0±1.2 at 2 and 5 minutes, respectively. Five women required the use of additional uterotonics within the first 24 hours. In all these 5 cases additional uterotonic was administered intra-operatively; the uterine tone at 2 and 5 minutes in these cases was 6.5/6.5, 10/8, 7/8.5, 8/6 and 3/4, and the time of request was 4, 11, 7,15 and 5 minutes after administration of carbetocin. The overall calculated blood loss (mean±SD) was 770±407 mL and the overall incidence of hypotension post carbetocin administration was 30%. At a recruitment rate of 24 cases/month, we plan to recruit the last patient by April 2015.

Discussion: The overall mean uterine tone seems to be adequate in most patients, however, 23 and 15% of patients had uterine tone <7 at 2 and 5 minutes, which in theory could prompt the request for additional uterotonics. It seems however, that the decision of requesting additional uterotonic is not based entirely on the assessment of tone, as only 3 of the 5 women receiving additional treatment exhibited tone <7. Final discussion and conclusion will be presented at the meeting.

References: 1) J Obstet Gynaecol Can 2009; 31: 980-93; 2) Can J Anesth 2012; 59: 751-7; 3) Can J Anesth 2013 ;60:1054-60; 4) Can J Anesth 2014; 61:242-8.

SOAP 2015