Actively Recruiting
Interscalene vs Phrenic-sparing Blocks in Obesity and Effect of Maximum Inspiratory Pressure
Led by University of North Carolina, Chapel Hill · Updated on 2026-01-28
68
Participants Needed
1
Research Sites
94 weeks
Total Duration
On this page
Sponsors
U
University of North Carolina, Chapel Hill
Lead Sponsor
A
American Society of Regional Anesthesia
Collaborating Sponsor
AI-Summary
What this Trial Is About
The goal of this clinical trial is to learn whether a phrenic-sparing nerve block can lower early breathing problems after shoulder surgery in adults with obesity, and whether a simple breathing-strength test (maximum inspiratory pressure, MIP) helps identify who is at higher risk. The main questions are: Does the phrenic-sparing approach reduce breathlessness or oxygen need in the recovery room (30-60 minutes after arrival)? Do patients have similar pain control and opioid use compared with the standard interscalene block (ISB)? Are there any breathing-related complications or unplanned admissions within 24 hours? Researchers will compare the phrenic-sparing block (infraclavicular + distal suprascapular) to the standard ISB, both commonly used at UNC. Participants will: Have a quick MIP breath test before surgery (and, if age ≥65, a brief thigh muscle ultrasound). Be randomly assigned to receive either the standard ISB or the phrenic-sparing block (both ultrasound-guided and part of routine care). Receive usual anesthesia/surgery; have a brief recovery check at 30-60 minutes (breathlessness score, oxygen use, oxygen level). Have pain medicines recorded from anesthesia start to PACU discharge; the team may review the chart up to 24 hours and make a short follow-up call (24-48 hours).
CONDITIONS
Official Title
Interscalene vs Phrenic-sparing Blocks in Obesity and Effect of Maximum Inspiratory Pressure
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Age 18 years or older confirmed by self-report and medical chart
- Body mass index (BMI) of 35 kg/m2 or higher at pre-operative clinic visit
- Scheduled for elective unilateral shoulder surgery under general anesthesia at UNC Hospitals
- Planned use of a single-injection regional brachial-plexus block for postoperative pain relief
- Able to perform a maximum inspiratory pressure (MIP) test with two reproducible efforts
- Able to read or understand English and provide written informed consent
You will not qualify if you...
- Emergency or trauma shoulder surgery or case converted to open surgery
- Pregnancy confirmed by urine test on day of surgery
- Prisoner status or unable to give legal consent
- Severe pulmonary disease including GOLD stage 3-4 COPD, restrictive lung disease with FVC below 50%, baseline dyspnea Borg score 3 or higher, or home oxygen use
- Severe heart disease such as severe valvular disease, congestive heart failure NYHA Class III or IV, or obstructive coronary artery disease with angina
- Neuromuscular disorders affecting breathing muscles or known diaphragmatic paralysis
- Blood clotting problems or infection at block injection sites
- Anemia with hemoglobin below 10 g/dl or significant hemoglobin disorders
- Allergy to bupivacaine, dexamethasone, or ultrasound gel
- Chronic opioid use over 100 mg oral morphine equivalents daily in the three months before surgery
- Previous enrollment in this trial or participation in another conflicting interventional study
- Expected inability to comply with postoperative assessments due to cognitive impairment or early transfer to another facility
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Trial Site Locations
Total: 1 location
1
University of North Carolina Hospitals
Chapel Hill, North Carolina, United States, 27599
Actively Recruiting
Research Team
M
Monika Nanda
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
SINGLE
Allocation
RANDOMIZED
Model
PARALLEL
Primary Purpose
TREATMENT
Number of Arms
2
Not the Right Trial for You?
Explore thousands of other clinical trials that might be a better match.
Sign up to get personalized trial recommendations delivered to your inbox.
Already have an account? Log in here