New nerve block may ease breathing after shoulder surgery in obese patients

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age ≥ 18 years (self-report, confirmed on chart). * Body-mass index ≥ 35 kg m\^2 at the pre-operative clinic visit (chart). * Scheduled for elective unilateral shoulder surgery (arthroscopy, arthroplasty, rotator cuff repair, reverse arthroplasty) under general anesthesia at UNC Hospitals * Planned use of a single-injection regional brachial-plexus block for postoperative analgesia (anesthesia record). * Able to perform a maximal-inspiratory-pressure (MIP) maneuver at screening, producing two reproducible efforts (bedside test) * Able to read or understand English and provide written informed consent (consent discussion). Exclusion Criteria: * Emergent or trauma shoulder procedure or case converted to open surgery (schedule/chart). * Pregnancy confirmed by point-of-care urine test on day of surgery (POC test). Prisoner status or legal incapacity to consent (chart/interview). * Severe pulmonary disease: GOLD stage 3-4 COPD, restrictive lung disease unrelated to obesity with FVC \< 50 % predicted, baseline dyspnea Borg ≥ 3, or home oxygen therapy (pulmonary clinic notes, patient interview). * Severe heart disease- Severe valvular heart disease, Congestive Heart Failure NYHA Class III or IV, Obstructive Coronary Artery Disease with Angina * Neuromuscular disorders affecting respiratory muscles (e.g., ALS, myasthenia gravis) or known diaphragmatic paralysis (chart). * Coagulopathy (platelets \< 100 × 10/ L or INR \> 1.5) or local infection at block sites (pre-op labs/assessment). * Anemia and hemoglobinopathies: Hgb \<10 g/dl, clinically significant hemoglobinopathy. * Allergy to bupivacaine, dexamethasone, or ultrasound gel (self-report). * Chronic opioid use \> 100 mg oral-morphine equivalents per day in the three months preceding surgery (medication history, PDMP query). * Prior enrolment in this trial or planned participation in another interventional study that might confound outcomes (research registry). * Anticipated inability to comply with postoperative assessments (e.g., profound cognitive impairment, expected early transfer to outside facility) as judged by the investigator