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Background and Aims This prospective, randomized, observer-blinded trial aimed to compare the efficacy of ultrasound-guided proximal and distal intercostobrachial nerve block (ICBNB) as adjuncts to supraclavicular brachial plexus block (SC-BPB) for upper arm arteriovenous access procedures. We hypothesized that the proximal approach would achieve higher success rates than the distal approach.

Methods Sixty end-stage renal disease patients undergoing upper arm arteriovenous access surgery were randomly assigned to receive either proximal (n=30) or distal (n=30) ICBNB. Both groups received a 10-mL mixture of 0.25% levobupivacaine-1% lidocaine with epinephrine 2.5 μg/mL. A blinded observer recorded successful ICBNB (primary endpoint), defined as sensory blockade at the medial upper arm and axilla. Imaging, needling times, and block-related complications were recorded. Subsequently, SC-BPB with 30 mL of local anesthetic was performed in both groups. Surgical anesthesia, postoperative pain scores, intravenous tramadol requirement, and sensory blockade duration were also recorded.

Results The proximal group had a higher percentage of sensory blockade at the axilla (97% vs 73%, P=0.026) but comparable blockade at the medial upper arm (97% vs 97%, P=1.000). Ultrasound image acquisition was faster with the proximal approach (13.4 [10.0-18.3] vs 18.8 [14.0-26.5] seconds, P=0.015). No differences were observed in needling time, ICBNB onset time, block-related complications, surgical anesthesia, or postoperative outcomes.

Conclusions Proximal ICBNB consistently reduced sensation at the medial upper arm and axilla, while one-fourth of distal blocks spared the axillary area. Both approaches, combined with SC-BPB, effectively facilitated upper arm arteriovenous access procedures; however, proximal ICBNB might be preferable for axillary surgery.