Comparison Between Ultrasound-guided Intercostobrachial Nerve Block With Supraclavicular Block Versus Ultrasound -Guided Erector Spinae Block With Supraclavicular Block for Medial Arm A-V Fistula Surgery: Observer Blinded Randomized Comparative Study

Intravenous access will be obtained with an 18-gauge intravenous (IV) cannula in the contralateral upper limb of the surgical site and monitors (pulse oximeter, electrocardiography, non-invasive blood pressure and capnography) will be applied.

All patients will receive 5 L/min of oxygen was delivered via a face mask.

In all patients, the SCPB was performed before the assigned supplemental block. Patients were placed supine with the head turned approximately 30° away from the surgical side and a small towel positioned between the scapulae to optimize access. After aseptic preparation, a high-frequency linear US probe (6 - 12 MHz) of ultrasound US machine (LOGIQ P7) covered with a sterile sheath was placed in the coronal-oblique plane just superior to the clavicle and lateral to the sternocleidomastoid muscle to visualize the subclavian artery medially, the brachial plexus divisions as a cluster of hypoechoic round structures lateral to the artery, and the first rib and pleura as hyperechoic lines deep to the artery.

Lidocaine 1% was injected at the entry site of the needle, Using an in-plane lateral-to-medial approach, a 22-G, 80-mm insulated block needle was advanced under continuous US guidance toward the "corner pocket" bordered by the subclavian artery medially, the first rib inferiorly, and the brachial plexus laterally. After negative aspiration, 5 - 10 mL of was injected into the corner pocket, and the needle was redirected to deposit additional 3 - 5 mL aliquots around the remaining plexus divisions to ensure circumferential spread, for a total of a mixture of 15 ml each of 0.5% bupivacaine and 2% lidocaine.

In group (I), following the SCPB, the intercostobrachial nerve (ICBN) was blocked using Ultrasound-Guided Intercostobrachial Nerve Block Procedure after SCPB, the ICBN was blocked under US guidance at the mid-axillary level. The patient was positioned supine with the arm abducted to 90°. A high-frequency linear probe (6 - 12 MHz) was placed transversely over the mid-axillary line at the level of the 2nd-3rd intercostal spaces. The axillary vein and artery were first visualized, then the probe was adjusted superficially to identify the fascial plane between the subcutaneous tissue and the serratus anterior muscle.