Supraclavicular Nerve Block - Technique and Efficacy

Introduction

The supraclavicular block also provides the most range of sensory blocking of any brachial plexus (BP) technique, making it excellent for offering dense, quick onset, and adequate anesthesia and analgesia for operations ranging from the shoulder joint and mid-humerus proximally to the hand distally. According to the experts, the supraclavicular approach is one of the most successful and safest procedures. The technique was developed in 1911 by Kulenkampff as a landmark-based strategy. However, the associated risk of pneumothorax contributed to its discontinuation. Kapral and colleagues advocated using dynamic ultrasonography to guide needle progress in the supraclavicular position. The supraclavicular block is favorable because the brachial plexus nerves are densely packed with this technique, and the onset time is frequently quick.

What Is the Anatomy Brachial Plexus?

The C5 (cervical) and C6 nerve roots constitute the superior trunk of the brachial plexus, the C7 nerve root produces the intermediate trunk, and the C8 and T1 (thoracic) nerve roots make the inferior trunk. Because the plexus is so densely packed at this site, local anesthetic quickly covers all of the plexus nerves, resulting in a fast, dense block. Carefully palpate the interscalene groove down to the middle of the clavicle to locate them.

What Are the Indications of the Supraclavicular Block?

The supraclavicular block is used for primary regional anesthesia during surgery and postoperative pain management throughout the distal two-thirds of upper limbs or from the mid-humerus to the digits. Very distant branches, particularly the ulnar nerve, may be spared.

What Are the Contraindications of the Supraclavicular Block?

• The supraclavicular block is contraindicated in the same way as the peripheral nerve block (for example, in case of patient rejection, local anesthetics allergy, infection at the injection site, any malignancy at the site of injection, and bleeding disorders).

• The most common consequence linked with this block is pneumothorax. Using a shorter needle (two inches) can reduce the likelihood of pneumothorax. The supraclavicular block induces diaphragmatic hemiparesis in around 50 percent of patients, with only a little loss in forced vital capacity (FVC). A massive pneumothorax (air leak in the space between the lungs and chest wall) is characterized by a sudden cough and shortness of breath.

• A more superficial brachial plexus block might be explored for individuals on anticoagulant treatment.

• Local anesthetic dissemination has led to cases of diaphragmatic paresis, and pneumothorax occurrences have developed in individuals suffering from severe lung illness.

• A regional block is not recommended if the distribution of the block has preexisting neurologic impairments.

What Are the Instruments Needed to Perform Supraclavicular Block?

• Povidone-iodine or Chlorhexidine gluconate disinfectant solution.

• High-frequency ultrasonic probe with sterilized probe sleeve and gel.

• For superficial layers, local anesthesia, Lidocaine one percent is commonly used.

• Regional block local anesthetic solution Bupivacaine or Ropivacaine 0.5 percent for postoperative analgesia, and two percent Lidocaine or 1.5 percent Mepivacaine for short onset.

• 10 to 20 mL (milliliters) injection with an extending tube with a short bevel block needle.

What Is the Procedure for Supraclavicular Block?

Landmarks:

• The posterior border of the sternocleidomastoid (SCM) muscle is palpated at the C6 level and the fingers are rolled laterally along the anterior scalene muscle until they are in the inter scalene groove (the groove may be more challenging to distinguish below the C6 level due to the overlaying omohyoid muscle).

• Then, the fingers are moved laterally beneath the interscalene groove until they are about 0.3 inches from the middle of the clavicle. This is the point where the needle will be inserted for the first time. Then, standing at the patient's head, the needle is pointed toward the axilla.

Nerve Stimulation:

• The nerve stimulator is calibrated at 1.0 to 1.2 mA (milliampere) at first. Flexion or extension of the fingers at 0.5 mA or less indicates proper needle insertion.

• The brachial plexus can be deep in this position. However, it usually reaches around 0.7 to 1.5 inches. The aspiration of bright red blood indicates subclavian artery penetration, indicating that the needle is too medial.

• Musculocutaneous nerve stimulation (biceps contractions) frequently suggests that the injection is excessively lateral.

• Scapular movement implies the needle is anterior to the plexus, while pectoralis muscle contraction suggests the needle is posterior.

Local Anesthetic:

In most individuals, 30 to 40 milliliters of local anesthetic solution is adequate to block the plexus.

Additional Procedures:

• The inter-costo-brachial nerve is anterior to and somewhat superior to the axillary artery, innervating the epidermis on the upper medial aspect of the forearm.

• A subcutaneous "wheal" of local anesthetic is placed on the attachment of the pectoralis muscle on the bone of the upper arm to the inferior aspect of the underarm to block this nerve.

• The skin wheel is positioned as close to the elbow as feasible.

Position of the Probe:

• Using a linear, high frequency (5 to 12 megahertz). The finest transverse image of the brachial plexus is from the coronal oblique plane; again, a cross-sectional (axial) view shows the nerves as hypoechoic circles with hyperechoic rings ("bundle of grapes").

• The probe is placed precisely above the clavicle in the supraclavicular fossa on the neck. The plexus will be arranged as trunks or segments at this level and will be positioned lateral and slightly above the subclavian artery at a depth of 0.7 to 1.5 inches.

Approach:

• The needle is placed into the ultrasound probe's lateral end and moved parallel to the ultrasound beam until it reaches the plexus.

• The needle is retained inside the ultrasonic beam path; this technique ensures that users can see the whole needle from shaft to tip.

• If the needle imaging is lost during the block technique, the needle is not advanced further until the image can be re-visualized by probe adjustment.

Injection:

• Observing the distribution of the local anesthetic during the injection allows for real-time correction of the needle tip location if the distribution is not adequate.

• The "donut supraclavicular block sign" (produced by the local anesthetic encircling the nerves) is a favorable sign that the drug is being disseminated appropriately.

• A local anesthetic may be applied precisely by injecting tiny aliquots (5 milliliters) and monitoring the local anesthetic spread.

Conclusion

A supraclavicular block is often administered with the assistance of a nurse by an anesthesiologist. All practitioners must be aware of the risks associated with regional block anesthetics. Most individuals have minimal problems, although a minority may experience transient brachial plexus paralysis.