Determining the Minimal Effective Volume (MEAV95) for Interscalene Brachial Plexus Block for Surgical Anesthesia (MEAV 95)

Sunnybrook Health Sciences Centre

Status and phase: Unknown; Phase 4

Conditions: Shoulder Pain

Treatments: Procedure: Dose of of ropivacaine 0.75% used in block procedure

Study type: Interventional

Funder types: Other

Identifiers

NCT01703130

126-2012

Details and patient eligibility

About

Interscalene block (ISB) consistently demonstrates superior pain relief after shoulder surgery. However, patients can experience complications such as blurred vision, hoarseness and shortness of breath with the standard volumes of local anesthetic used in contemporary practice. Patients with respiratory diseases are precluded because of the potential effects on respiration. However, they are then exposed to the risks of general anesthesia and opioid medications which can also have detrimental effects on respiration. Ultrasound guided ISB can reduce the local anesthetic volume required to produce anesthesia for shoulder surgery; this may reduce the complications from ISB to allow patients previously unable to benefit to have this technique, such as patients with obesity and respiratory disease. In order to do so the investigators will use an up-down methodology to find the minimum volume of local anesthetic to provide sufficient anesthesia for shoulder surgery.

Enrollment: 60 estimated patients

Sex: All

Ages: 18 to 75 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients undergoing elective arthroscopic shoulder surgery in the sitting position
• Patients aged >=18 and <=75 years
• ASA I-III

Exclusion criteria

• Patient refusal for surgery under ISBPB with sedation
• Lack of capacity to provide informed consent
• Pre-existing COPD, unstable asthma or diaphragmatic dysfunction
• Coagulopathy
• Infection at injection site
• Allergy to local anesthetics
• Opioid tolerance (>30mg oral morphine or equivalent/day for >1 week)
• BMI>40
• Inability to complete questionnaires and assessments (consent, follow-up phone call) due to language barrier
• Pregnancy or lactation

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: Quadruple Blind

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60 participants in 1 patient group

Local Anesthestic Dose

Experimental group

Treatment:

Procedure: Dose of of ropivacaine 0.75% used in block procedure