Supraclavicular block

Surgical approach (typical operations using this block)

Common indications: surgery on arm/forearm/wrist/hand (e.g. ORIF distal radius, tendon repairs, carpal tunnel, hand trauma washout, AV fistula formation).
Surgeon typically: applies tourniquet (upper arm), positions arm abducted/supinated as required, uses diathermy; may require immobility and dense sensory block.
- Tourniquet pain can occur despite good distal block; may need supplemental analgesia/sedation or proximal block/GA.
Duration varies: minor hand surgery 30–90 min; trauma/ORIF often 1–2+ hours.

Anaesthetic management (typical)

Type of anaesthesia: Regional (supraclavicular block) ± sedation; or GA + block for analgesia.
Airway: usually none (spontaneous ventilation) if awake/sedated; if GA then SGA/ETT depending on aspiration risk, duration, positioning, surgical needs.
How painful: block provides excellent intra-op anaesthesia for distal upper limb; tourniquet can be painful; post-op analgesia usually very good for 8–18 h depending on LA and adjuncts.
Monitoring: standard AAGBI; IV access; resus drugs and lipid emulsion immediately available.
Plan for failure: top-up with distal nerve blocks (median/ulnar/radial), local infiltration, conversion to GA if needed.

Overview

Brachial plexus block at the level of trunks/divisions where nerves are compact (“spinal of the upper limb”).
Provides dense anaesthesia for upper limb distal to shoulder; often spares intercostobrachial nerve (T2) → may not cover medial upper arm/tourniquet pain.
Best for: elbow, forearm, wrist, hand surgery; less reliable for shoulder/proximal humerus (interscalene preferred).

Relevant anatomy (high-yield)

Landmarks: clavicle, sternocleidomastoid (SCM), interscalene groove, subclavian artery, first rib, pleura (cupola).
Brachial plexus lies lateral/posterolateral to subclavian artery, superior to first rib, superficial to pleura.
First rib acts as a backstop; pleura lies inferomedial—needle too medial/inferior risks pneumothorax.
Phrenic nerve: less frequently blocked than interscalene but still possible (hemidiaphragmatic paresis).
Other nearby structures: dorsal scapular artery, suprascapular artery, subclavian vein (more medial/anterior), recurrent laryngeal nerve (rare involvement).

Indications

Anaesthesia/analgesia for surgery distal to shoulder: elbow/forearm/wrist/hand, including trauma and day-case surgery.
Analgesia adjunct to GA to reduce opioids and improve recovery.
Facilitates manipulation/reduction and painful dressing changes.

Contraindications

Absolute: patient refusal, LA allergy (true IgE rare), infection at site, inability to cooperate/consent, uncontrolled bleeding/haemodynamic instability requiring immediate GA.
Relative: coagulopathy/therapeutic anticoagulation (follow RA-UK/ASRA principles; compressibility limited), severe respiratory disease (risk of phrenic block/pneumothorax), contralateral pneumonectomy/diaphragm palsy, pre-existing neuropathy, severe obesity/poor sonoanatomy.
Caution: ipsilateral recurrent laryngeal nerve palsy or contralateral vocal cord palsy (rare but potential airway compromise if bilateral).

Preparation and consent (FRCA viva style)

Explain: aims (anaesthesia + analgesia), expected sensory/motor loss, duration, need for limb protection, possibility of failure and conversion to GA, and specific risks (pneumothorax, vascular puncture, nerve injury, LAST, diaphragmatic paresis).
Check: side/site marking, allergies, anticoagulants, baseline neuro exam, respiratory status, pregnancy status if relevant.
Equipment: ultrasound with high-frequency linear probe, sterile cover/gel, block needle, extension tubing, incremental syringe dosing, aspiration, monitoring, oxygen, suction, airway kit, intralipid 20%.

Technique (ultrasound-guided: common UK practice)

Position: supine, head turned away, ipsilateral arm by side; slight head-up may reduce venous engorgement; ensure comfortable access to supraclavicular fossa.
Probe: transverse in supraclavicular fossa, parallel to clavicle; identify subclavian artery, first rib (hyperechoic line with acoustic shadow), pleura (sliding).
Target: brachial plexus cluster lateral/superior to artery (“grapes/honeycomb”). Aim for spread around plexus, often at the “corner pocket” (between artery and first rib) to capture inferior trunk (ulnar distribution).
Needle: in-plane lateral-to-medial (commonly) to keep pleura in view; advance to perineural plane; inject small aliquots with frequent aspiration; observe circumferential spread.
Volume: typically 15–25 mL depending on LA choice, patient size, and desired duration; use lowest effective volume to reduce phrenic involvement and toxicity risk.
Adjunct blocks: intercostobrachial nerve (T2) field block for tourniquet/medial upper arm; consider ulnar/median/radial supplementation if patchy.

Local anaesthetic choices (examples; always calculate maximum safe dose)

Short/medium duration: lidocaine 1–2% (often with adrenaline 1:200,000) for faster onset; consider alkalinisation per local policy.
Longer duration: ropivacaine 0.5% or levobupivacaine 0.25–0.5% for prolonged analgesia.
Mixing LAs: may combine for onset + duration, but toxicity is additive; do not exceed combined maximum dose.
Adjuvants: dexamethasone (perineural vs IV depends on policy; evidence suggests prolongation), clonidine/dexmedetomidine (prolongation but bradycardia/sedation).

Assessment of block

Sensory: cold/light touch in median (index finger), ulnar (little finger), radial (dorsum thumb web space), musculocutaneous (lateral forearm).
Motor: wrist/finger extension (radial), finger abduction (ulnar), thumb opposition (median), elbow flexion (musculocutaneous).
Time: onset often 10–30 min depending on LA; do not rush to incision if incomplete—supplement early.

Complications (recognition and management)

Pneumothorax: pleuritic pain, dyspnoea, hypoxia, reduced breath sounds; may be delayed. Manage with oxygen, imaging, needle decompression/chest drain as indicated; involve seniors.
Vascular puncture/haematoma: subclavian artery/vein. Apply pressure; avoid multiple passes; consider anticoagulation status.
LAST: tinnitus, metallic taste, agitation, seizures, arrhythmias, cardiovascular collapse. Stop injection, call for help, airway/100% O2, treat seizures, lipid emulsion, ALS modifications.
- Lipid (typical adult regimen): 20% intralipid 1.5 mL/kg bolus over ~1 min then 0.25 mL/kg/min infusion; repeat bolus if unstable; max ~10 mL/kg in first 30 min (follow local guideline).
Nerve injury: intraneural injection/high pressure, paraesthesia/pain on injection. Avoid injection against resistance; stop if pain/paraesthesia; document and follow-up.
Hemidiaphragmatic paresis: dyspnoea, reduced FVC; usually transient. Avoid high volumes; consider alternative approach in severe lung disease.
Horner’s syndrome: ptosis, miosis, anhidrosis; reassure; indicates spread to sympathetic chain.
Recurrent laryngeal nerve block: hoarseness; caution if contralateral palsy.

Postoperative care

Limb protection: sling, avoid heat/trauma, warn about insensate limb; written instructions for day-case patients.
Analgesia plan: regular paracetamol/NSAID (if appropriate), opioid rescue; counsel on rebound pain when block wears off (take analgesia before sensation returns).
Neurovascular checks if trauma/cast: pain out of proportion, paraesthesia, pallor, pulselessness → urgent surgical review (compartment syndrome not prevented by block).

Talk me through how you would perform an ultrasound-guided supraclavicular block safely.

Structure your answer: preparation → anatomy/sonoanatomy → needle approach → injection strategy → safety checks.

Preparation: consent (including pneumothorax/LAST), IV access, monitoring, resus + lipid available, asepsis, time-out and correct side.
Sonoanatomy: identify subclavian artery, first rib, pleura; locate plexus lateral/superior to artery.
Needle: in-plane lateral-to-medial, keep tip visible, avoid medial/inferior direction toward pleura.
Injection: incremental 3–5 mL aliquots with aspiration; aim for circumferential spread; consider “corner pocket” to cover inferior trunk.
Safety: stop if pain/paraesthesia or high injection pressure; monitor for LAST; reassess block before surgery.

What are the key complications of supraclavicular block, and how would you recognise and manage pneumothorax?

Complications: pneumothorax, LAST, vascular puncture/haematoma, nerve injury, hemidiaphragmatic paresis, Horner’s, hoarseness (RLN), infection.
Recognition of pneumothorax: dyspnoea, pleuritic chest pain, hypoxia, tachycardia, reduced air entry; may be delayed post-op.
Immediate management: oxygen, ABC approach, call for help, consider bedside ultrasound/CXR; if tension suspected treat immediately (needle decompression) then chest drain.

A patient develops tinnitus and a metallic taste during injection. What is happening and what do you do next?

Likely early LAST from intravascular injection/systemic absorption.
Stop injecting; call for help; maintain airway and give 100% oxygen; treat seizures with benzodiazepine; avoid large propofol doses if unstable.
Start lipid emulsion per guideline; manage arrhythmias with ALS modifications (avoid lidocaine; cautious adrenaline doses).

Why might a supraclavicular block not cover tourniquet pain, and what can you do about it?

Tourniquet pain often mediated by intercostobrachial nerve (T2) and medial cutaneous nerve of arm; may be outside brachial plexus coverage.
Management: intercostobrachial field block in axilla/medial upper arm; systemic analgesia (opioid/ketamine), sedation; consider GA if severe or prolonged.

Compare supraclavicular with interscalene and infraclavicular approaches (indications and major risks).

Interscalene: best for shoulder/proximal humerus; high phrenic nerve block rate; less reliable ulnar distribution.
Supraclavicular: best for distal to shoulder; dense block; pneumothorax risk (reduced with ultrasound); some phrenic involvement possible.
Infraclavicular: good for distal arm; lower pneumothorax risk than supraclavicular; useful with catheter; deeper/closer to axillary vessels.

What ultrasound features help you avoid pneumothorax during supraclavicular block?

Identify first rib as hyperechoic line with shadow—acts as protective barrier; keep needle tip above rib.
Visualise pleural line and lung sliding; keep needle trajectory away from inferomedial pleura.
Maintain continuous needle tip visualisation; use shallow angle; avoid “blind” advancement.

Block failure: the patient has preserved sensation in the little finger after 20 minutes. What does this suggest and how would you manage it?

Suggests inferior trunk/ulnar nerve sparing—often due to inadequate spread in the “corner pocket”.
Management: reassess with ultrasound; consider targeted top-up in corner pocket (within safe dose limits) or perform ulnar nerve block at forearm/wrist; ensure tourniquet coverage separately.
If time-critical or inadequate despite supplementation: convert to GA.

How do you minimise the risk of nerve injury during peripheral nerve blockade?

Avoid intraneural injection: never inject with severe pain/paraesthesia; stop and reposition.
Use ultrasound to keep tip visible; inject small aliquots; monitor opening injection pressure (avoid high resistance).
Avoid deep sedation so patient can report symptoms; document baseline deficits and post-op findings.

What factors increase the risk of LAST in supraclavicular block and how can you reduce it?

Risk factors: high vascularity, large volumes, potent LAs, low body weight, extremes of age, pregnancy, hepatic/cardiac disease, inadvertent intravascular injection.
Risk reduction: calculate max dose, use lowest effective volume, incremental injection with aspiration, consider adrenaline marker dose, ultrasound guidance, avoid bilateral high-volume blocks.

A COPD patient needs wrist surgery. Would you choose a supraclavicular block? What are your considerations and alternatives?

Consider respiratory reserve: risk of hemidiaphragmatic paresis and pneumothorax may be poorly tolerated.
If proceeding: minimise volume, meticulous ultrasound technique, avoid heavy sedation, counsel regarding dyspnoea; have low threshold for alternative plan.
Alternatives: infraclavicular or axillary block (lower pneumothorax risk), or distal forearm blocks (median/ulnar/radial) for hand surgery; GA if necessary.