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Minimum Effective Volume of Ropivacaine 7.5 mg/ml for the Lateral and Sagittal Infraclavicular Brachial Plexus Block

This study has been completed.
Information provided by (Responsible Party):
Lars Marius Ytrebo, University Hospital of North Norway Identifier:
First received: December 14, 2011
Last updated: September 9, 2012
Last verified: September 2012
Systemic LA toxicity is an important complication of regional anesthesia. Lowering the LA dose is one of the strategies to reduce this risk. For upper limb blocks it is well documented that ultrasound guidance allows a significant lower dose of LA for interscalene and axillary blocks than with guidance by peripheral nerve stimulation. However, a corresponding difference has not yet been found for supraclavicular and infraclavicular blocks. The aim of the present study is to define the minimum effective volume of ropivacaine 7.5 mg/ml when using the LSIB method.

Condition Intervention Phase
Drug: Ropivacaine
Phase 4

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Single Blind (Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Minimum Effective Volume of Ropivacaine 7.5 mg/ml for the Lateral and Sagittal Infraclavicular Brachial Plexus Block When Using Guidance by Both Ultrasound and Nerve Stimulation.

Resource links provided by NLM:

Further study details as provided by Lars Marius Ytrebo, University Hospital of North Norway:

Primary Outcome Measures:
  • The primary outcome measure is the minimum effective volume of ropivacaine 7.5 mg/ml providing a successful infraclavicular block (LSIB) in 50% of the patients (MEAV50). [ Time Frame: 30 minutes ]

Estimated Enrollment: 25
Study Start Date: February 2012
Study Completion Date: July 2012
Primary Completion Date: June 2012 (Final data collection date for primary outcome measure)
Intervention Details:
    Drug: Ropivacaine
    Dosage. Onset time
    Other Name: Naropin
Detailed Description:

The blocks will be performed as previously described, by an anesthesiologist with LSIB expertise. The lateral, medial and posterior cords are the target of infra-clavicular brachial plexus blocks. During a prescan we will record if they can be visualized by ultrasound and indicate their positions periarterially. The deep location of the cords may hamper their identification, especially that of the medial cord. We describe the cord positions with reference to the short-axis (cross-sectional) view of the axillary artery, which is compared to a clockface having 12 o'clock ventrally. In a former MRI study it was found that the cords were usually located in a sector from 3-11 o'clock (the 3-11 sector) and within a distance of 2 cm from the midaxis of the axillary artery. The point closest to the cords was at 8 o'clock, immediately outside the arterial wall. Point of needle insertion is at the intersection between the lower edge of the clavicle and the medial surface of the coracoid process. We direct the needle tip to the 8 o'clock position and observe the spread of LA from this position. On demand we adjust the needle position to secure a complete fill of the 3-11 sector with LA (multiple injections).

The block needle has an electrical cable. Prior to LA injections we test if a minimal electric output (0.2 mA/0.1 msec duration) elicits a motor response. If such a response is obtained, the needle is withdrawn (in steps of 1 mm), until the motor response disappears. This is to reduce the risk of intraneural injection.


Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Patients of American Society of Anesthesiologists physical status (ASA) I-II
  • Scheduled for surgery distal to the elbow.
  • Duration of surgery >1 hour.
  • Age 18-65 years,
  • Body mass index 20-35 kg/m2

Exclusion Criteria:

  • Pregnancy
  • Any contraindication to regional anesthesia
  • Patients on major opioids because of chronic pain
  • Atrioventricular block
  • Pacemaker
  • Diabetes
  • Peripheral neuropathy
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Please refer to this study by its identifier: NCT01493986

University Hospital of North Norway
Tromsø, Troms, Norway, 9038
Sponsors and Collaborators
University Hospital of North Norway
Principal Investigator: Lars M Ytrebo, Professor University Hospital of North Norway
  More Information

Responsible Party: Lars Marius Ytrebo, Professor, University Hospital of North Norway Identifier: NCT01493986     History of Changes
Other Study ID Numbers: UNorthNorway
Study First Received: December 14, 2011
Last Updated: September 9, 2012

Keywords provided by Lars Marius Ytrebo, University Hospital of North Norway:
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