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

Phase 4

• Conditions: Shoulder Pain
• Interventions: Procedure: Dose of of ropivacaine 0.75% used in block procedure

• Registration Number: NCT01703130
• Lead Sponsor: Sunnybrook Health Sciences Centre

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Study Start: 2012-10
• Study First Submitted: 2012-10-04
• Study First Submitted QC: 2012-10-05
• Study First Posted: 2012-10-10
• Status Verified: 2014-05
• Last Update Submitted: 2014-05-29
• Last Update Posted: 2014-06-02
• Primary Completion: 2014-12
• Study Completion: 2014-12

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 60

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Local Anesthestic Dose	Dose of of ropivacaine 0.75% used in block procedure	-

Primary Outcome Measures

Name	Time	Method
MEAV95 of ropivacaine 0.75%	30 minutes post injection	to determine the MEAV95 of ropivacaine 0.75% at the level of root C5-6 using the dose-finding protocol. The success of surgical anesthesia is defined by the presence of sensory blockade (no sensation/score of 0 to pinprick testing) 30 minutes post injection of local anesthetic

Secondary Outcome Measures

Name	Time	Method
Motor blockade	30 minutes	The C5 myotome covers the deltoid muscle (the most powerful motion being shoulder abduction) and the biceps brachii muscle. Biceps brachii is also innervated by C6. Therefore, motor blockade will be assessed by testing shoulder abduction and forearm flexion. Motor function will be classified as present (any movement) or absent (no movement)
Bedside spirometry	30 minutes post block, 30min post-surgery, and 2 hours post surgery	Bedside spirometry (FEV1, FVC, PEFR) and Pulse oximetry on air: at baseline, 30 minutes post block, 30min post-surgery, and 2 hours post surgery
Diaphragmatic excursion	30 minutes post block, and 2 hours post surgery	Diaphragmatic excursion: ultrasound examination at baseline, 30 minutes post block, and 2 hours post surgery
Complications	30 minutes	Complications: Hoarseness, Horner's syndrome, intravascular injection
Pain Scores on Visual Analog Scale	at baseline, after surgery at 30 and 60 minutes in the PACU, and at 1 hour intervals until discharge	Visual analog scale (VAS) - at baseline, after surgery at 30 and 60 minutes in the PACU, and at 1 hour intervals until discharge
Total opioid consumption until discharge	24 hours (at discharge)	Total opioid consumption until discharge
Opioid related side effects	24 hours (at discharge)	Opioid related side effects: nausea, vomiting, dizziness, pruritis
Time to first analgesic use	within 24 hours post surgery	Time to first analgesic use in hospital and after discharge

Trial Locations

Locations (1)

Sunnybrook Health Sciences Centre - Holland Orthopaedic and Arthritic Centre; 🇨🇦 Toronto, Ontario, Canada