U/S Guided Rhomboid Intercostal Block Combined With Sub-Serratus Plane Block vs Type 2 Pectoral Nerve Block

Patients will be randomly allocated into three groups based on a computerized randomization table with specific ID for each patient (23 per group). Each patient will be prepared in Preoperative Holding Area with sedation with midazolam 0.05mg/kg patients allotted to the RIB group were positioned in the lateral decubitus position with the breast on the operating side lying superiorly. The ipsilateral arm was abducted from the chest to move the scapula laterally. The RISS was performed after application of antiseptic solution. A high-frequency using a 6-13 MHz linear ultrasound probe set to B mode (SonoSite M-turbo ultrasound machine) was placed medial to the medial border of the scapula in the oblique sagittal plane. The landmarks, i.e., the trapezius muscle, rhomboid muscle, intercostal muscles, pleura, and lung, were identified in the ultrasound. Under aseptic conditions, a 100-mm 21-gauge needle was inserted at the level of T5-6 in the ultrasound view. A single dose of 20-mL 0.25% bupivacaine was injected in the interfascial plane between the rhomboid major and intercostal muscles. The spread of the local anesthetic solution under the rhomboid muscle was visualized by ultrasonography. Thereafter, the ultrasound probe was moved caudally and laterally to identify the tissue plane between the serratus anterior and external intercostal muscles for the sub-serratus block at the T8-9 level. The needle was advanced from its previous position, and an additional 20 mL of 0.25% bupivacaine was injected. All block procedures were performed by the same anesthesiologist who had administered the RIB and RISS blocks in more than 30 cases before this study. In control group (Group C), no block intervention was performed.

After disinfection, using 30 mL of levobupivacaine 0.25% (10 mL between pectoralis minor muscle and pectoralis major muscle, and 20 mL between the pectoralis major muscle and serratus muscle). With the patient in supine position. (Group B) After shifting to the operative area, all patients underwent conventional monitoring procedures including electrocardiography, noninvasive monitoring of blood pressure, and peripheral oxygen saturation measurements. Intravenous access was gained using a 22-gauge intravenous needle, and isotonic saline was infused at a rate of 15 mL kg-1 h-1. Anesthetic management was in accordance with a standard protocol. Anesthesia was induced with pre-oxygenation for 3 min followed by intravenous injection of midazolam (0.05 mg/kg), fentanyl (0.1 µg/kg), propofol (1-2 mg/kg), and atracurium (0.5 mg/kg). An endotracheal tube was used for positive-pressure ventilation to maintain the end-tidal carbon dioxide level of 35-40 mmHg.

Anesthesia was maintained using 2% sevoflurane with 50% oxygen, fentanyl (0.1 µg kg-1 min-1), and propofol (100 µg kg-1 min-1). Additionally, atracurium (0. 1 mg/kg) was administered according to the surgical protocol. Surgery (Unilateral conservative mastectomy) was started. The anesthetic dose was adjusted to maintain blood pressure within 20% of the baseline value. An additional dose of intravenous fentanyl (0.1 µg kg-1 min-1) was injected as needed. If the blood pressure decreased by > 20% from the baseline value, 250 mL of 0.9% (physiologic) saline and ephedrine (0.1 mg/kg) were administered. If the heart rate decreased to less than 50 bpm, atropine (0.5 mg/kg) was administered. At the end of the surgery, the effect of atracurium was reversed using neostigmine and atropine as needed. After the surgery, the endotracheal tube was removed when the patient fulfills criteria of extubation. Then the patient will be transferred to the PACU.

Data will be collected:

1. Intraoperative assessment: (readings will be taken just after induction and every 15 min throughout surgery)
2. Heart rate intraoperative.
3. Mean arterial blood pressure intraoperative.
4. Analgesic consumption: recorded during intraoperative period to maintain maximum 20% change of basal vital signs after exclusion of other causes. (Intraoperative fentanyl consumption)
5. Postoperative:
6. Recovery time: the time taken to be fully awake and responding to commands.
7. Pain score: VAS score at 0, 3, 6, 9,24h post-operative.
8. Hemodynamic: pulse, B.P (systolic, diastolic, and mean blood pressure) at 0,3,6,9,24h postoperative.
9. Side effects (nausea, vomiting, hematoma, hypotension, bradycardia).
10. Rescue analgesia plane will be given for VAS≥4 using non-steroidal anti-inflammatory analgesic (ketorolac 30 mg) and VAS≥6 using opioid (3mg morphine). Time of the first rescue analgesia together with frequency and total dose of the given drug through the 24 hours will be recorded.
11. Hospital discharge.

Primary outcome:

1. Total morphine consumption in first 24 hours post operative.
2. VAS score postoperative.

Secondary outcome:

1. Heart rate intraoperative.
2. Mean arterial blood pressure intraoperative.
3. Timing of first rescue analgesia.
4. Intraoperative fentanyl consumption.
5. Side effects (nausea, vomiting, hematoma, hypotension, bradycardia).
6. Body mass index (BMI).