Effects of Technique on the Local Anesthetic Dose Required for Interscalene Brachial Plexus Block

The recruitment status of this study is unknown because the information has not been verified recently.
Verified August 2008 by Sunnybrook Health Sciences Centre.
Recruitment status was  Recruiting
Sponsor:
Information provided by:
Sunnybrook Health Sciences Centre
ClinicalTrials.gov Identifier:
NCT00731146
First received: August 5, 2008
Last updated: NA
Last verified: August 2008
History: No changes posted
  Purpose

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 be randomly assigned to a group to undergo ISBPB under ultrasound or nerve stimulator guidance. Each group will initially receive 10mL of local anesthetic. 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 2.5mL, while a success will cause the volume to decrease by the same amount. We hypothesize that the minimum effective anesthetic volume in 50% of patients will be significantly lower in the ultrasound guided group than in the nerve stimulator group. We further hypothesize that this lower volume will lead to a decreased rate of complications.


Condition Intervention
Arthroscopic Shoulder Surgery
Other: Ultrasound Minimum Effective Anesthetic Volume
Other: Nerve Stimulator Minimum Effective Anesthetic Volume

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Effects of Ultrasound Guidance on the Minimum Effective Anesthetic Volume Required for Interscalene Brachial Plexus Block Versus Nerve Stimulator Guidance

Resource links provided by NLM:


Further study details as provided by Sunnybrook Health Sciences Centre:

Primary Outcome Measures:
  • Pain Rating as based on 11 point NRS scale [ Time Frame: within 30 minutes or less post-surgery ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Diaphragmatic Function (as assessed by diaphragmatic movement on ultrasound) [ Time Frame: within 30 minutes post-block ] [ Designated as safety issue: No ]

Estimated Enrollment: 80
Study Start Date: August 2008
Estimated Study Completion Date: July 2009
Estimated Primary Completion Date: February 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: 1 - Ultrasound
Participants will receive an ultrasound guided interscalene brachial plexus block
Other: Ultrasound Minimum Effective Anesthetic Volume
Each sequential participant in this group will be assigned a dose based on the success or failure of the previous participant's block. The starting dose will be 10mL of 0.5% ropivacaine. Each success will decrease the dose by 2.5mL and each failure will subsequently increase the dose by 2.5mL.
Active Comparator: 2 - Nerve Stimulator
Participants will receive a nerve stimulator guided interscalene brachial plexus block
Other: Nerve Stimulator Minimum Effective Anesthetic Volume
Each sequential participant in this group will be assigned a dose based on the success or failure of the previous participant's block. The starting dose will be 10mL of 0.5% ropivacaine. Each success will decrease the dose by 2.5mL and each failure will subsequently increase the dose by 2.5mL.

Detailed Description:

This will be a randomized, single-blind, up-down sequential allocation study. Patients will be randomly assigned to one of two groups, and receive either an ultrasound-guided or nerve-stimulator guided interscalene brachial plexus block. The initial local anesthetic volume in both groups will be 10mL. The outcome of each patient's block will determine the dose for the subsequent patient. When an effective ISBPB is observed, as defined by a NRS (patient-rated pain on a scale from 0 to 10) rating of 0 within 30 minutes post-surgery, the volume of local anesthetic solution used for the next patient will be decreased by 2.5mL. Conversely, when an ineffective ISBPB is observed, the volume of local anesthetic used for the next patient will be increased by 2.5mL.

The goal of this study is to determine the minimum effective anesthetic volume of ropivacaine 0.5% providing analgesia in patients when using either ultrasound or a nerve stimulator to guide placement of the block. The primary outcome measure will be the pain score of the patient on a numeric rating score during the 30 minutes after surgery.

A number of previous studies have suggested that ultrasound-guidance is beneficial for peripheral nerve blocks in terms of block performance time, success rates, and block quality. Some studies have also shown that ultrasound-guidance can reduce the volume of local anesthetic needed to perform a successful block. This study may reveal that less local anesthetic is needed under ultrasound guidance than under nerve stimulator, which may potentially reduce some of the common complications of ISBPB.

We hypothesize that ISBPB done under ultrasound guidance will have a lower minimum effective local anesthetic volume than ISBPB done under nerve stimulation. Further, we hypothesize that the lower volume will reduce the incidence of some of the complications of ISBPB.

Using lower volumes of local anesthetic while still maintaining effective analgesia may reduce some of the common complications of ISBPB. It may also allow this beneficial analgesic technique to be given to patients with some respiratory risk factors who are currently unable to receive it.

  Eligibility

Ages Eligible for Study:   18 Years to 80 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Patients receiving interscalene brachial plexus block for arthroscopic shoulder surgery

Exclusion Criteria:

  • ASA >III, and body mass index (BMI) >35, pre-existing chronic obstructive pulmonary disease (COPD), unstable asthma, psychiatric history, renal or hepatic impairment, allergy to ropivacaine, and opioid tolerance (>30 mg oral morphine or equivalent per day).
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00731146

Contacts
Contact: Colin J McCartney, MD 416-480-6100 ext 3230 cjlmccartney@sympatico.ca

Locations
Canada, Ontario
Sunnybrook Health Sciences Centre Recruiting
Toronto, Ontario, Canada, M4N 3M5
Contact: Colin J McCartney, MD    416-480-6100 ext 3230    cjlmccartney@sympatico.ca   
Principal Investigator: Colin J McCartney, MD         
Sub-Investigator: Andrew McNaught, MD         
Sub-Investigator: Uma D Shastri, MD         
Sponsors and Collaborators
Sunnybrook Health Sciences Centre
Investigators
Principal Investigator: Colin J McCartney, MD Sunnybrook Health Sciences Centre
  More Information

No publications provided

Responsible Party: Dr. Colin McCartney, Sunnybrook Health Sciences Centre
ClinicalTrials.gov Identifier: NCT00731146     History of Changes
Other Study ID Numbers: SHSCA02
Study First Received: August 5, 2008
Last Updated: August 5, 2008
Health Authority: Canada: Ethics Review Committee

Keywords provided by Sunnybrook Health Sciences Centre:
Interscalene Brachial Plexus Block
Regional Anesthesia
Ultrasound guided peripheral nerve block
Minimum Effective Anesthetic Volume
Nerve Stimulator guided peripheral nerve block

Additional relevant MeSH terms:
Anesthetics
Central Nervous System Depressants
Physiological Effects of Drugs
Pharmacologic Actions
Central Nervous System Agents
Therapeutic Uses

ClinicalTrials.gov processed this record on September 22, 2014