Minimum anesthetic volume (MEV90) for interscalene block to numb supraclavicular nerves
Minimum Effective Volume (MEV90) of Local Anesthetic Required for Ultrasound-Guided Interscalene Block for Supraclavicular Nerve Block: A Dose-Finding Study
This study will test different small volumes of bupivacaine given with an ultrasound-guided interscalene block to see which volume reliably numbs the supraclavicular nerves in adults having shoulder surgery.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 55 (estimated) |
| Ages | 18 Years and up |
| Sex | All |
| Sponsor | Hospital del Trabajador de Santiago Academic / other |
| Locations | 1 site (Providencia) |
| Trial ID | NCT07338916 on ClinicalTrials.gov |
What this trial studies
This prospective dose-finding study uses a biased coin up-and-down sequential design to determine the MEV90 of bupivacaine 0.5% with epinephrine for supraclavicular nerve sensory block when performed as a single-shot ultrasound-guided interscalene block. The initial volume is 12 mL and subsequent volumes are adjusted by 2 mL steps based on the prior patient's response, with a maximum allowed volume of 30 mL. All blocks are performed under ultrasound by experienced anesthesiologists (≥60 prior ISBs) following standard safety protocols, and outcomes focus on sensory coverage of the supraclavicular distribution relevant to shoulder and clavicle surgery. The goal is to determine whether a single interscalene injection can reliably cover the supraclavicular nerves or whether a separate superficial cervical plexus block is needed.
Who should consider this trial
Good fit: Adults aged 18 or older with ASA I–III, BMI 18–35 kg/m², weight ≥50 kg, scheduled for shoulder arthroscopy and able to provide informed consent are ideal candidates.
Not a fit: Patients with coagulopathy, significant pulmonary, renal or hepatic disease, allergy to local anesthetics, pregnancy, pre-existing neuropathy, prior ipsilateral cervical or supraclavicular surgery, or contralateral hemidiaphragmatic or vocal cord paralysis may not receive benefit or may be excluded.
Why it matters
Potential benefit: If successful, the results could lower anesthetic doses, improve pain coverage for shoulder and clavicle procedures, and reduce the risk of local anesthetic toxicity.
How similar studies have performed: Biased coin up-and-down dose-finding designs have been used successfully to define minimum effective volumes for regional blocks, but specific MEV90 data for supraclavicular nerve coverage from a single interscalene injection remains limited.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * Age ≥ 18 years * ASA physical status I to III * Body Mass Index (BMI) between 18 and 35 kg/m² * Weight ≥ 50 kg * Scheduled for shoulder arthroscopy requiring an interscalene brachial plexus block for analgesia * Able to provide informed consent Exclusion Criteria: * Inability to provide informed consent * Coagulopathy (platelet count ≤100,000; INR ≥1.4) * Significant pulmonary disease (restrictive or obstructive) * Renal insufficiency (creatinine ≥1.2 mg/dL) * Hepatic insufficiency (transaminases ≥100 U/L) * Allergy to local anesthetics * Pregnancy * Pre-existing neuropathy * Previous surgery in ipsilateral cervical or supraclavicular region * Contralateral hemidiaphragmatic paralysis or vocal cord paralysis
Where this trial is running
Providencia
- Hospital del Trabajador — Providencia, Chile (Recruiting)
Study contacts
- Study coordinator: Germán Aguilera, MD
- Email: german.aguilera@gmail.com
- Phone: +56985205514
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.