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

NCT ID: NCT01493986

Last Updated: 2012-09-11

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE4
• Total Enrollment: 25 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2012-02-29
• Study Completion Date: 2012-07-31

Brief Summary

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.

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 If such a response is obtained, the needle is withdrawn (in steps of 1 mm), until the motor response disappears.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.

Conditions

Pain

Keywords

Ropivacaine; Brachial plexus

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Interventions

Ropivacaine

Dosage. Onset time

Intervention Type: DRUG

Other Intervention Names

Naropin

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University Hospital of North Norway

OTHER

Sponsor Role: lead

Responsible Party

Lars Marius Ytrebo

Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Lars M Ytrebo, Professor

Role: PRINCIPAL_INVESTIGATOR

University Hospital of North Norway

Locations

University Hospital of North Norway

Tromsø, Troms, Norway

Countries

Norway

Other Identifiers

UNorthNorway

Identifier Type: -

Identifier Source: org_study_id