Dexamedatomidine vs. Dexamethasone in Rhomboidal Intercostal Plain Block and Subserratus Block in Breast Surgery

The patient will be placed in lateral position. A linear ultrasound transducer of frequency 6-12 MHz will be placed medial to the lower border of the scapula in a sagittal plane. A 38-mm 22-gauge will be inserted under real-time in-plane from craniocaudal between the rhomboid major and intercostal muscles. After negative aspiration, single injection of 10 ml of the local anesthetic mixture will be administered at the T6 7 level. The spread of local anesthetic solution under the rhomboid muscle will be visualized by ultrasonography. Then the ultrasound probe will be moved caudally and laterally to identify the tissue plane between the serratus anterior and external intercostal muscle for the sub-serratus block at T 8-9 level. The needle will be advanced from its previous position and a further of 10 ml of the local anesthetic mixture will be injected.

"Fentanyl (1 μg/kg), propofol (2-3mg/kg) and atracurium (0.3-0.5 mg/kg) will be injected intravenously 3-5 minutes after oxygenation. A single-lumen endotracheal tube will be used to complete ventilation. The ventilator ventilation mode is volume control mode, and the patient's end-expiratory carbon dioxide level is maintained at 35-40 mmHg throughout the anesthesia process. During the anesthesia maintenance phase, 2% sevoflurane mixed with 60% oxygen.~After general anaesthesia induction, all patients will receive RISS block with different local anesthetic drug mixture according to randomization."

Patients will receive general anaesthesia and RISS block with 20 ml of 0.25% bupivacaine + 1 Mcg/kg dexamedatomidine in 2 mL.

Patients will receive general anaesthesia and RISS block with 20 ml of 0.25% bupivacaine + 8mg dexamethasone in 2 mL.

Patients will receive general anaesthesia and RISS block with 20 ml of 0.25% bupivacaine+ 2 mL normal saline.