Poor uterine tone after the birth of a baby can cause excess bleeding (called postpartum hemorrhage or PPH). This is a major cause of maternal death worldwide. Uterotonic drugs are used to improve the muscle tone of the uterus after birth, and these are effective at reducing the incidence of PPH. The Society of Obstetricians and Gynecologists of Canada (SOGC) has recommended a single dose of 100 mcg of carbetocin at elective cesarean delivery to promote uterine contraction. In a study performed at Mount Sinai Hospital, the investigators have shown that smaller doses of carbetocin (14.8 mcg) are effective in achieving adequate uterine tone at elective cesarean section. In these dose-finding studies, women with multiple pregnancies have been excluded. Because women with multiple pregnancy have a higher risk of severe PPH, uterine atony, hysterectomy, prolonged hospital stay and death, it is plausible that a higher dose of carbetocin is required. This question remains unanswered. The hypothesis is that the ED90 of carbetocin in women with twin pregnancy undergoing elective cesarean delivery under regional anesthesia is greater than 20 mcg but less than 100 mcg.
There is a lack of consensus as to what the optimal uterotonic regime is globally. Furthermore, variability in the international guidelines regarding the choice of first line uterotonic in prevention of PPH adds to the confusion. With the widespread availability of carbetocin in some developed countries, including Canada, the question of which uterotonic to adopt and at which dose becomes even more difficult to ascertain. Studies that have currently been published suggest the ED90 doses of carbetocin and oxytocin provide adequate uterine contraction with possibly fewer side effects associated with the lower dose regimens. There is evidence to suggest that lower doses of both carbetocin provide equivalent uterine contractions with a better side effect profile in patients with a singleton pregnancy. However, there is no clinical dosing data specifically for patients with twin pregnancy. The results of our study will provide guidance to obstetric and anesthetic providers worldwide when deciding what dose of carbetocin to use in women with twin pregnancy.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
30
Carbetocin administered intravenously, over 1 minute following delivery of the fetal head.
Mount Sinai Hospital
Toronto, Ontario, Canada
Uterine tone 2 minutes: questionnaire
Uterine tone, defined as satisfactory or unsatisfactory by the obstetrician at 2 minutes after completion of the carbetocin injection.
Time frame: 2 minutes
Uterine tone 5 minutes: questionnaire
Uterine tone, defined as satisfactory or unsatisfactory by the obstetrician at 5 minutes after completion of the carbetocin injection.
Time frame: 5 minutes
Additional uterotonics administered
The drug, dosage and timing of any additional uterotonic medication given during surgery.
Time frame: 1 hour
Estimated blood loss
Blood loss will be calculated through the difference in hematocrit values assessed prior to surgery and 24 hours after the cesarean delivery.
Time frame: 24 hours
Intravenous fluid administered during surgery
The total volume (ml) of fluid administered from entering the operating room to skin closure.
Time frame: 2 hours
Hypotension: systolic blood pressure less than 80% of baseline
Systolic blood pressure \< 80% of baseline, from drug administration until end of surgery
Time frame: 2 hours
Tachycardia: heart rate greater than 130% of baseline
Heart rate \> 130% of baseline, from drug administration until end of surgery
Time frame: 2 hours
Bradycardia: heart rate less than 70% of baseline
Heart rate \< 70% of baseline or a heart rate \< 50bpm, from drug administration until end of surgery
Time frame: 2 hours
Presence of ventricular tachycardia: ECG
Presence of ventricular tachycardia as recorded by ECG, from drug administration until end of surgery
Time frame: 2 hours
Presence of atrial fibrillation: ECG
Presence of atrial fibrillation as recorded by ECG, from drug administration until end of surgery
Time frame: 2 hours
Presence of atrial flutter: ECG
Presence of atrial flutter as recorded by ECG, from drug administration until end of surgery
Time frame: 2 hours
Presence of nausea: questionnaire
The presence of nausea and number of episodes, from drug administration until end of surgery, as reported by the patient
Time frame: 2 hours
Presence of vomiting: questionnaire
The presence of vomiting and number of episodes, from drug administration until end of surgery
Time frame: 2 hours
Presence of chest pain: questionnaire
Any presence of chest pain, from drug administration until end of surgery, as reported by the patient
Time frame: 2 hours
Presence of shortness of breath: questionnaire
Any presence of shortness of breath, from drug administration until end of surgery, as reported by the patient
Time frame: 2 hours
Presence of headache: questionnaire
Any presence of headache, from drug administration until end of surgery, as reported by the patient
Time frame: 2 hours
Presence of flushing: questionnaire
Any presence of flushing, from drug administration until end of surgery
Time frame: 2 hours
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