Minimum Effective Volume of Local Anesthetic Using Ultrasound for Brachial Plexus Block
The purpose of this study is to determine the minimum effective volume of local anesthetic for interscalene brachial plexus block using ultrasound guidance and nerve stimulator guidance.
|Study Design:||Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Single Group Assignment
Masking: Double Blind (Subject, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
|Official Title:||Determination of the Minimum Effective Volume of Local Anesthetic Using Ultrasound Guidance for Interscalene Brachial Plexus Block|
- ED95 of bupivacaine minimum effective volume [ Time Frame: ED95 ] [ Designated as safety issue: No ]The ED95 of bupivacaine minimum effective volume determination in interscalene brachial plexus block using ultrasound guidance. [ Time Frame: every 10 minutes until 30 minutes, after 4 hours and after 6 hours post-block ]
- Diaphragmatic Function [ Time Frame: Diaphragmatic ] [ Designated as safety issue: No ]Diaphragmatic Function (as assessed by diaphragmatic movement on ultrasound) [ Time Frame: after 30 minutes, 4 hours and 6 hours post-block ]
- Post-surgery analgesia [ Time Frame: Analgesia ] [ Designated as safety issue: No ]Post-surgery analgesia [ Time Frame: after 4 hours and 6 hours post-block ]
|Study Start Date:||September 2009|
|Study Completion Date:||June 2011|
|Primary Completion Date:||June 2011 (Final data collection date for primary outcome measure)|
Drug: bupivacaine 0.5%
This will be a single group assignment, double-blind, up-down sequential allocation study. Interscalene brachial plexus block (ISBPB) is a common nerve block given to patients who are undergoing shoulder surgery. This block has a low, but still significant, rate of complications. Reducing the volume of local anesthetic given during the block may allow some of these complications to be avoided. Participants will undergo ISBPB under ultrasound and nerve stimulator guidance. Patients will initially receive 15mL of local anesthetic (bupivacaine 0.5% with epinephrine). The volume used for each subsequent patient depends upon the success or failure of the previous patient's block - a failure will cause the volume given to increase by 1.0 mL, while a success will cause the volume to decrease by the same amount.
The goal of this study is to determine the minimum effective anesthetic volume of bupivacaine 0.5% providing anesthesia in patients when using ultrasound and nerve stimulator to guide placement of the block. The secondary outcome will be the evaluation of diaphragmatic function and post-surgery analgesia.