///2012 Abstract Details
2012 Abstract Details2019-08-02T19:38:42-06:00

CARBETOCIN AT ELECTIVE CESAREAN DELIVERY: A DOSE FINDING STUDY

Abstract Number: T-7
Abstract Type: Original Research

Suresh ANANDAKRISHNAN MBBS, FRCA1 ; Mrinalini Balki MD, Associate professor2; Dan Farine MD, Professor3; Gareth Seaward MD, Professor4; Jose Carvalho MD, Professor5

Introduction: Carbetocin is an oxytocin derivative recommended in Canada as the uterotonic of choice (1) at elective cesarean sections (CS). It has been shown to reduce the use of additional uterotonics at CS compared with a bolus dose of oxytocin (2). Although the recommended dose is 100 mcg, a recent study showed no differences in efficacy between doses ranging from 80-120mcg (3), suggesting that lower doses might be effective, potentially reducing side effects. This study aimed to identify the minimal dose of carbetocin to produce effective uterine tone at elective CS.

Methods: We performed a randomized, double-blind, dose-finding study of carbetocin in five groups, 20, 40, 60, 80 and 100 mcg. Inclusion criteria were low risk patients undergoing elective CS under spinal anesthesia. Carbetocin was administered intravenously upon delivery of the anterior shoulder. Uterine tone was assessed by the obstetrician at one minute intervals for five minutes. Two minutes after administration, the obstetrician could request initiation of our normal oxytocin protocol at any time if required, or any other additional uterotonic. Adverse effects were recorded. Preoperative and postoperative hemoglobin and hematocrit values were obtained to assess operative blood loss. Our primary outcome was satisfactory uterine tone at 2 minutes after delivery.

Results: 120 patients were recruited. Overall, 7 (5.8%) patients had unsatisfactory uterine tone at two minutes, of which 5 required supplementary oxytocin. A further 11 patients received additional uterotonic within 4 hours. Therefore, a total of 16 (13.3%) patients required additional uterotonics. There was no significant difference between the groups in terms of uterine tone or need for additional uterotonic. Consequently, it was not possible to construct a dose-response curve. There were no significant dose related differences with regard to side effects, including hypotension (45% overall).

Discussion: We found no difference in efficacy between doses of 20-100 mcg during elective CS in low risk patients. However, there appears to be a high incidence of hypotension across all doses. It is possible that even lower doses of carbetocin may be sufficient to achieve satisfactory uterine tone, and further studies are required to investigate whether associated side effects may also be reduced.

References:

1. http://www.sogc.org/guidelines/documents/gui235CPG0910.pdf;

2. BJOG 2010;117:929–36;

3. SOAP 2011, Abstract 85



SOAP 2012