Ultrasound Guidance for Interscalene Brachial Plexus Block

Summary

This study has been designed to assess the possible advantages of using ultrasound imaging to block the brachial plexus (i.e., nerves of the upper limb) in patients undergoing shoulder surgery.

The ultrasound technique will be compared with the current gold standard, electrical nerve stimulation.

The aim of this study is to define which technique is better in terms of time to onset of anesthesia.

Conditions

• Shoulder
• Orthopedic Surgery
• Nerve Block

Interventions

PROCEDURE

Ultrasound-guided continuous interscalene brachial plexus block

With patients in the supine position, a high-frequency (10-12 MHz) ultrasound transducer in a sterile sheath will be applied to explore the interscalene region and locate the brachial plexus. The transducer will be positioned so as to image the C5 and C6 roots in a single view. Visualization of the C7 root in the same scan will be sought, but will not be required. A 50-mm, 20 G needle will be advanced in-plane from the postero-lateral side of the transducer. Injection of the local anesthetic will be performed in small aliquots while repositioning of the needle in order to optimize spread of the injectate around the nerve roots. At the end of the injection, a catheter will be threaded through the needle. The catheter will be positioned to lie deep and close to the imaged nerve roots.

PROCEDURE

Continuous interscalene brachial plexus block using electrical nerve stimulation

With patients in the supine position, the head will be rotated to the contralateral side. The interscalene groove will be palpated. A 35-mm, 20 G needle will be inserted at the estimated C6 level (cricoid cartilage) with a 30-45° angle to the skin. The needle will be advanced along a line joining the insertion site to the axilla. An electrical nerve stimulator will be used at an initial intensity of 1.0 mA (frequency: 2 Hz, pulse width: 0.2 ms). A musculocutaneous or axillary-nerve mediated twitch will be sought Injection of the local anesthetic will start with a visible motor response at a current \<0.5 mA. The catheter will be positioned to as to elicit a motor response at ≤0.4 mA.

DRUG

Ropivacaine

Block induction \[1% (wt/vol) solution\]: 20 ml (200 mg) Postoperative analgesia \[0.2% (wt/vol) solution\]: * Background infusion: 4 ml/h (8 mg/h) * Incremental on-demand dose: 2 ml (4 mg) * Lockout time: 15 min

DRUG

Paracetamol

1 g iv q8h

DRUG

Morphine

5 mg im prn q1h (in the postoperative period)

DRUG

Fentanyl

50 µg iv prn (in the intraoperative period)

PROCEDURE

General anesthesia

Will be given in case of block failure and/or patient discomfort intractable with fentanyl during the procedure. The technique will be left at the discretion of the attending anesthesiologist. Monitored anesthesia care will also be acceptable; the block will be considered as failed in that case as well.

Sponsors & Collaborators

• University of Parma

  lead OTHER

Principal Investigators

• Giorgio Danelli, MD · UO II Anestesia, Rianimazione e Terapia Antalgica, AOU Parma

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

85 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2008-05-31

Primary Completion

2009-11-30

Completion

2009-11-30

Countries

• Italy

Study Locations