Patients undergoing radical mastectomy are randomly assigned to receive, in addition to standard general anesthesia, a block of the erector spinae plane with ropivacaine at a dose of 0.5% for the control group (n = 13) and ropivacaine at a dose of 0.5% more dexmedetomidine at 0.3 mcg kg (n = 15) for the intervention group. General anesthesia was induced using anxiolysis with midazolam at 30 mcg / kg corrected weight, as induction, propofol at a dose of 1.5 - 2 mg kg, opioid analgesia with fentanyl at a dose of 3 mcg / kg weight corrected with 30% according to ideal weight initial bolus dose, and dose as required, neuromuscular relaxation with cisatracurium at a dose of 0.1 mg / kg.
This prospective, randomized, double-blind study is designed to evaluate the postoperative analgesic efficacy of dexmedetomidine as an adjunct to ropivacaine in erector spinae block in patients undergoing radical mastectomy. The investigators hypothesis is that the administration of ropivacaine 0.5% associated with dexmedetomidine in the blockade via the plane in the erector spinae is less effective in controlling acute postoperative pain in radical mastectomy than the administration of ropivacaine 0.5% without dexmedetomidine.