This randomized, double-blinded, parallel-group trial compares the effect of three ultrasound-guided regional anesthesia techniques on diaphragmatic function in elective shoulder surgery. The interscalene block (ISB), the gold standard, frequently causes phrenic nerve paralysis and hemi-diaphragmatic paresis. The suprascapular (SSNB) and costoclavicular (CCB) blocks preserve analgesia while sparing the phrenic nerve, but direct comparative data among all three are limited.
Seventy-five ASA I-II patients aged 18-70 scheduled for elective shoulder surgery will be randomized 1:1:1 (25 per group) using computer-generated allocation with sealed opaque envelopes. ISB: 10 mL 0.25% bupivacaine with dexmedetomidine 0.5 µg/kg; SSNB: 10 mL of the same mixture; CCB: 20 mL of the same mixture. All blocks are ultrasound-guided and performed before a standardised general anaesthetic.
Diaphragmatic excursion is measured by M-mode ultrasound of both hemidiaphragms at baseline (pre-induction), 30 minutes after the block, and in the PACU at a train-of-four ratio ≥0.9. Hemi-diaphragmatic paresis is graded as Complete (>75% reduction or paradoxical movement), Partial (25-75%), or Normal (0-25%). The primary outcome is its incidence. Secondary outcomes include VAS pain at rest and movement (1, 3, 6, 12, 24 h), analgesic consumption, time to first rescue analgesia, block performance time, complications, and patient satisfaction.