Ultrasound Guided Infraclavicular Brachial Plexus Block Using Levo-bupivacaine Alone or Combined With Dexmedetomidine for Hand and Forearm Surgeries

Technique for ultrasound guided infraclavicular brachial plexus block:

Preliminary scan

• The patient is positioned supine with the arm abducted to 90°(or resting by their side if unable to do so).
• The probe is placed immediately medial to the coracoid process in the parasagittal plane.
• Identify the pectoralis major and minor muscles superficially and the axillary artery and vein(s) deep to this. The vein is usually caudad relative to the artery.
• The cords of the brachial plexus are seen as either hypoechoic or hyperechoic structures positioned around the axillary artery. The lateral cord is lateral (cephalad) to the artery, the medial cord medial (caudad),and the posterior cord posterior (deep). They can be difficult to visualize but are usually positioned closely to the artery.

Ultrasound settings

• Probe: high-frequency (>10MHz) linear broadband probe.
• Settings: MB-resolution/general.
• Depth: 3-6cm.
• Orientation: parasagittal.
• Needle: 50-100mm depending on depth of plexus. Technique
• An in-plane approach is recommended, inserted from the cephalad end of the transducer.
• Needle tip visualization may be challenging as the needle angle can be quite steep.
• Prepare the skin with 0.5% chlorhexidine in 70% alcohol. Wait until the skin is dry.
• Anaesthetize the skin with a subcutaneous injection of 1% lidocaine at the point of needle insertion.
• The needle is first advanced posterolateral to the artery to deposit local anesthetic around the posterior cord, 5 o'clock position on artery.
• After careful aspiration LA is injected in small aliquots, observing the spread of the LA which ideally occurs behind and up both sides of the artery forming a 'U' shape around the artery, 1-9 o'clock around the artery.
• If medial (caudad) spread is not observed then reinsertion of the needle between the axillary artery and vein, adjacent to the medial cord may be required.

Inclusion criteria

• Age: 20-65 years old.
• American society of anesthesiologist physical status (ASA): I-II.
• Operation: forearm & hand surgeries.

Exclusion criteria

• Patients with chronic pain
• Those using chronic analgesic medications
• History of brachial plexus injury
• Allergy to the study drugs
• Hepatic or renal insufficiency or infection at the site of injection