Evaluating Efficacy of Intravenous Carbetocin Versus Intramyometrial Injection of Adrenaline in Reducing Blood Loss

Uterine fibroids, affecting 20-50% of all women ,and are benign tumors that arise from myometrial cells of the uterine smooth muscle tissue. Although most are asymptomatic, fibroids can often cause abnormal uterine bleeding, iron deficiency anemia, pelvic pressure symptoms and pain

Women with myomatous uteri have an increased number of blood supply which may cause excessive bleeding during myomectomy. The excessive bleeding may result in blood transfusions and prolonged hospital stays. A variety of methods are used to reduce bleeding during myomectomy including preoperative administration of gonadotropin-releasing hormone (GnRH) agonists, uterine artery tourniquet, vaginal misoprostol, intravenous tranexamic acid, intramyometrial injections of bupivacaine plus adrenaline and vasopressin, chemical dissection with Mesna (sodium-2-mercaptoethanesulfonate), perioperative injection of ascorbic acid, and, recently, carbetocin.

Currently, there are several strategies for the treatment of fibroids. Still, myomectomy, the surgical removal of myomas, is an important treatment option for symptomatic leiomyomas, especially in women who wish to preserve their uteri.This can be accomplished via laparotomy, laparoscopy or hysteroscopy.

Oxytocin is a hormone secreted from the posterior pituitary and exerts its effect on the uterus by producing uterine contractions during labor and delivery. Because of this contractile feature, synthetic oxytocin analogs are used in the treatment of postpartum uterine atony and hemorrhage. Based on its ability to attenuate blood loss, oxytocin has been evaluated in gynecologic procedures, including hysterectomies, myomectomies, and endometrial resections. Although the expression of oxytocin receptors is thought to be strictly related to pregnancy, their presence has been demonstrated in the leiomyomatous uterus.

Carbetocin was first introduced to control postpartum hemorrhage, but its manageability and efficacy soon made it an interesting option for gynecologic surgeons. Given its longer half-life compared with oxytocin and its ample bioavailability, carbetocin could represent a very useful tool during myomectomy, administered either intravenously or intramuscularly Following promising reports on the effectiveness of carbetocin in reducing intraoperative blood loss, hemoglobin drop, and need for postoperative blood transfusions.

Adrenaline is a potent vasoconstrictive agent that has a high risk of cardiovascular effects if an intravascular instillation is performed. The vasoconstrictive effect of adrenaline on tissue lasts longer than that of vasopressin.

Bupivacaine is a local anesthetic that causes vasodilatation at clinical doses, but lower doses appear to cause vasoconstriction. Bupivacaine has shown to have a vasoconstrictive activity in concentrations of ≤ 0.25%, with duration of its action between 4 and 24 h when used for local infiltration. The use of a combination of bupivacaine and low dose of adrenaline in order to minimize the cardiovascular effects of the latest without interfering with the vasoconstrictive effects on haemostasis has been documented.

The myometrial injection of adrenaline plus bupivacaine was one of the evaluated methods showing significantly reduced blood loss and shorter duration of surgery compared to placebo

Eligibility Criteria:
Inclusion Criteria:

* Women aged 25-50 years old.
* Women who will undergo abdominal myomectomy because of symptomatic stage 3-6 fibroids, according to FIGO staging (Laughlin-Tommaso et al., 2017), with the number of myomas not exceeding five based on the preoperative ultrasonography (US).

Exclusion Criteria:

* Women with previous myomectomy.
* Pregnant and postmenopausal women.
* Women with preoperative hemoglobin concentration \<10 g/dL,
* women who are candidate for and choosing vaginal or laparoscopic myomectomy.
* History of preoperative embolization or hormone therapy (GnRH analogues), cervical and broad ligament myoma, number of myomas more than five on preoperative US, myoma FIGO stages 1,2,7 and 8 (Munro et al., 2011)
* Patients with allergy or contraindications to carbetocin or epinephrine, such as coronary artery disease, asthma, epilepsy, migraine, kidney, and hepatic disease.