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Dosage of Mepivacaine in Ultrasound Axillary Block

This study has been completed.
Information provided by (Responsible Party):
Samuel Perov, Wayne State University Identifier:
First received: November 23, 2011
Last updated: December 7, 2011
Last verified: December 2011

The use of ultrasonography as an adjunct to regional anesthesia has significantly increased in recent years. Brachial plexus blockade by an axillary approach is amenable to the use of ultrasound guidance. Real time sonography of nerve structures ensures an optimal distribution of the block solution. When compared to other methods of nerve localization, sonography decreases: failure rate procedure time and the onset time for blockade. Furthermore, the use of ultrasound for peripheral nerve blockade demonstrates decreased procedure related complications such as nerve injury and unintentional vascular puncture.

Traditional axillary block techniques relying on surface anatomical landmarks require large volumes of local anesthetic, generally 40mL and greater. Utilizing the increased accuracy offered by ultrasound, some studies have shown that low volumes of local anesthetic can yield successful axillary plexus blockade. Therefore, the tradition of using large volumes of local anesthetic for axillary blocks, even without ultrasound, may not be warranted.

Although recent investigations support using a low volume of local anesthetic for brachial plexus blockade, there is a lack of outcome data from blinded randomised trials. The primary objective of this study was to evaluate 2 different volumes of local anesthetic for axillary blockade: 1) 20mL or 2) 30 mL. For the 2 different volumes used in this study, a 1.5% solution of mepivacaine was chosen due to its widespread clinical use in axillary blocks, which is secondary to: rapid onset of action, intermediate duration of effect, and relative low cost. The primary outcome was block success rate for outpatients undergoing distal upper limb surgery. Secondary objectives included comparing the 2 volumes with respect to: time required to perform the block, and onset of sensory and motor blockade.

Condition Intervention
Nerve Block
Neuromuscular Blockade
Drug: Mepivacaine

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Double Blind (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Effective Low Dosage of Mepivacaine in Ultrasound Guided Axillary Block in Patients Undergoing Distal Upper Extremity Surgery

Resource links provided by NLM:

Further study details as provided by Samuel Perov, Wayne State University:

Primary Outcome Measures:
  • Successful Block [ Time Frame: 30 minutes ]

    Definitions of successful block Functional successful block: Sensory score of 0-1 in all 4 territories and motor score of 0-1 in 3 of 4 territories within 30 minutes of needle extraction.

    Surgical successful block: no required intraoperative supplemental local anesthetic, light sedation <25mcg/kg/min propofol and absence of general endotracheal anesthesia.

Secondary Outcome Measures:
  • Time required until onset of sensory blockade. [ Time Frame: 30 minutes ]

    Onset of Sensory blockade: Examined every 5 minutes following needle extraction using a blunt needle at 4 specific anatomic locations corresponding to radial, ulnar, median, and musculocutaneous distributions and compared with contralateral side using same stimulus.

    Onset of Motor Blockade: Examined every 5 minutes following needle extraction. Wrist flexion: median nerve; wrist extension: radial nerve; abduction of 5th finger or straight finger adduction: ulnar nerve; elbow flexion (with forearm supinated): musculocutaneous nerve.

  • Time taken until Onset of Motor Blockade [ Time Frame: 30 minutes ]
    Onset of Motor Blockade: Examined every 5 minutes following needle extraction. Wrist flexion: median nerve; wrist extension: radial nerve; abduction of 5th finger or straight finger adduction: ulnar nerve; elbow flexion (with forearm supinated): musculocutaneous nerve.

Enrollment: 64
Study Start Date: April 2010
Study Completion Date: September 2010
Primary Completion Date: August 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Mepivacaine, Ultrasound Axillary Block
Group 1) 20mL 1.5% mepivacaine Group 2) 30mL 1.5% mepivacaine
Drug: Mepivacaine
Group 1) 20mL 1.5% mepivacaine, one dose Group 2) 30mL 1.5% mepivacaine, one dose

  Show Detailed Description


Ages Eligible for Study:   18 Years to 80 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Orthopedic forearm, wrist and hand surgery
  • block procedure time less than 6 minutes
  • pre-block sedation using less than 2 mcg fentanyl and less than .04 mg midazolam,
  • patient consent to light pre-op sedation

Exclusion Criteria:

  • Elbow/arm surgery longer than 2 hours
  • ASA IV
  • BMI greater than 35
  • Pregnant patients
  • history of CVA or scarring in the axillary to elbow area
  • history of neurological impairment of either upper extremity
  • Any allergies to local anesthetics coagulopathy,
  • infection at the site of block
  • patients requiring opioid therapy for chronic pain
  Contacts and Locations
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Please refer to this study by its identifier: NCT01485653

Sponsors and Collaborators
Wayne State University
Principal Investigator: Samuel Perov, M.D. Wayne State University, Department of Anesthesiology
  More Information

Responsible Party: Samuel Perov, Dr Samuel Perov, Wayne State University Identifier: NCT01485653     History of Changes
Other Study ID Numbers: WSU irb# 0902006824
need to get ( Other Identifier: WSU IRB )
Study First Received: November 23, 2011
Last Updated: December 7, 2011

Keywords provided by Samuel Perov, Wayne State University:
Brachial Plexus

Additional relevant MeSH terms:
Anesthetics, Local
Central Nervous System Depressants
Physiological Effects of Drugs
Sensory System Agents
Peripheral Nervous System Agents processed this record on May 25, 2017