Infraclavicular block

11 min read Last updated April 8, 2026

Surgical approach

  • Not an operation; it is a regional anaesthetic technique used to facilitate upper limb surgery (typically elbow/forearm/wrist/hand).
  • Typical surgical procedures performed with infraclavicular block
    • Elbow: ORIF, arthroscopy, tendon repairs (variable tourniquet tolerance).
    • Forearm/wrist/hand: fracture fixation, tendon/nerve repairs, carpal tunnel release, Dupuytren’s surgery.
    • Often uses an upper arm tourniquet; may be painful without adequate block/sedation.

Anaesthetic management

  • Type of anaesthesia
    • Regional: infraclavicular block alone (awake/light sedation) or combined with GA.
    • GA: if block contraindicated/failed, patient preference, prolonged/complex surgery, inability to tolerate tourniquet.
  • Airway
    • If block-only: no airway device; ensure fasting status appropriate if sedation planned; oxygen and capnography if moderate/deep sedation.
    • If GA: SGA commonly suitable; ETT if aspiration risk, long duration, non-supine, significant comorbidity, or need for controlled ventilation.
  • Duration (typical)
    • Procedure-dependent: ~0.5–2 hours for many wrist/hand cases; longer for complex elbow/forearm fixation.
    • Block performance time: usually 5–15 minutes; onset 10–30 minutes depending on LA choice and technique.
  • How painful
    • Surgery: moderate to severe without regional; tourniquet discomfort may be limiting factor.
    • Post-op pain: can be significant (fracture fixation/tendon repair); catheter or long-acting LA can provide prolonged analgesia.
  • Analgesia plan
    • Multimodal: paracetamol + NSAID (if appropriate) + opioid rescue; consider dexamethasone (perineural or IV per local policy) to prolong analgesia.
    • If tourniquet expected: ensure dense block; consider light sedation (e.g., propofol/remifentanil) with monitoring.

Indications and coverage

  • Indications
    • Anaesthesia/analgesia for surgery distal to mid-humerus: elbow (variable), forearm, wrist, hand.
    • Good choice when you want to avoid phrenic nerve palsy (vs interscalene/supraclavicular) and when catheter placement is desired.
  • Dermatomal/terminal nerve coverage
    • Targets cords: lateral, posterior, medial cords around axillary artery → median, ulnar, radial, musculocutaneous nerves.
    • Intercostobrachial nerve (T2) not covered → medial upper arm/tourniquet pain may persist; consider separate block/infiltration if needed.
    • Medial cutaneous nerve of arm/forearm may be variably covered; assess clinically.

Contraindications and cautions

  • Absolute
    • Patient refusal, LA allergy (true), infection at site, inability to cooperate/unsafe sedation environment.
  • Relative / cautions
    • Anticoagulation/antiplatelets: treat as a deep, non-compressible block; follow current RA-UK/ASRA guidance and document risk–benefit.
    • Severe respiratory disease: generally safer than interscalene (lower phrenic risk) but still consider pneumothorax risk and sedation effects.
    • Pre-existing neuropathy: discuss potential for symptom exacerbation; careful documentation and technique.
    • Anatomical distortion (clavicle/shoulder trauma, prior surgery, radiotherapy) may reduce success/increase risk.

Anatomy (exam-focused)

  • Brachial plexus at infraclavicular level
    • Cords are named relative to the axillary artery: lateral, posterior, medial.
    • Typical ultrasound relationship (variable): lateral cord often anterolateral; medial cord anteromedial; posterior cord posterior to artery.
    • Axillary vein usually medial/anterior to artery; pleura lies deeper/medial depending on approach and habitus.
  • Key adjacent structures and risks
    • Pneumothorax risk (lower with ultrasound but not zero), particularly with medial/deep needle trajectory.
    • Vascular puncture: axillary artery/vein; haematoma risk increased with anticoagulation.
    • Nerve injury: intraneural injection/needle trauma; avoid high opening injection pressure and pain/paraesthesia on injection.

Techniques (ultrasound and nerve stimulation)

  • Patient positioning
    • Supine, head turned away; ipsilateral arm abducted slightly or resting by side (operator preference).
    • Optimise ergonomics: screen in line of sight; probe just inferior to clavicle, medial to coracoid (common approach).
  • Ultrasound approach (common practical description)
    • High-frequency linear probe (or curvilinear in large patients); identify axillary artery in short axis with cords around it.
    • In-plane needle (often lateral-to-medial) aiming to deposit LA to achieve circumferential spread around artery (especially posterior to artery for posterior cord).
    • Incremental injection with frequent aspiration; observe spread; reposition to cover 3–4 quadrants if needed.
    • Avoid pleura: keep needle tip visualised at all times; avoid steep medial/deep trajectory.
  • Nerve stimulator (if used)
    • Motor responses: radial (wrist/finger extension), median (wrist/finger flexion/pronation), ulnar (finger flexion/ulnar deviation), musculocutaneous (biceps).
    • Aim for distal response at low current; avoid injection if paraesthesia/pain or high resistance.
  • Single-shot vs catheter
    • Single-shot: reliable surgical anaesthesia for distal arm; duration depends on LA and adjuncts.
    • Catheter: useful for major trauma/hand replantation/complex surgery or severe post-op pain; secure well and monitor for infection/LA toxicity.

Local anaesthetic choice, volume, and adjuncts

  • Volume (typical adult, ultrasound-guided)
    • Often 20–30 mL total for single-shot (lower volumes may work with good spread; higher volumes increase risk of systemic toxicity).
    • Always calculate maximum safe dose (mg/kg) and account for any additional infiltration by surgeons.
  • LA options (examples; follow local policy)
    • Fast onset/shorter duration: lidocaine 1–2% (often with adrenaline).
    • Longer duration: ropivacaine 0.5–0.75% or levobupivacaine 0.25–0.5%.
    • Adrenaline (epinephrine) may reduce systemic absorption and acts as intravascular marker; avoid in end-artery compromise contexts per judgement.
  • Adjuncts
    • Dexamethasone (IV or perineural per local governance) can prolong analgesia; document route/dose.
    • Avoid mixing multiple LAs without clear rationale; increases complexity of toxicity calculations.

Assessment of block and troubleshooting

  • Assess sensory and motor function before incision
    • Median: palmar index finger sensation; thumb opposition/forearm pronation.
    • Ulnar: little finger sensation; finger ab/adduction.
    • Radial: dorsum of hand (1st web space); wrist/finger extension.
    • Musculocutaneous: lateral forearm sensation; elbow flexion.
  • Common reasons for failure
    • Inadequate posterior cord spread (radial sparing) if LA not deposited posterior to artery.
    • Missed musculocutaneous nerve (may have left sheath early); consider separate injection if clearly outside plexus sheath on ultrasound.
    • Tourniquet pain from intercostobrachial nerve (T2): consider subcutaneous ring block in axilla/upper medial arm infiltration.
  • Rescue strategies
    • Top-up with targeted ultrasound-guided supplementation (if safe dose allows) or distal peripheral nerve blocks.
    • Convert to GA if inadequate surgical conditions or patient discomfort; prioritise patient safety and communication with surgeons.

Complications and management

  • Local anaesthetic systemic toxicity (LAST)
    • Presentation: tinnitus, metallic taste, agitation, seizures → arrhythmias/cardiovascular collapse (may be delayed).
    • Immediate actions: stop injection, call for help, airway/oxygen/ventilation, treat seizures (benzodiazepine), start lipid emulsion per AAGBI/RA-UK guidance, manage arrhythmias (avoid large doses of propofol in unstable patient).
  • Pneumothorax
    • Symptoms: pleuritic pain, dyspnoea, hypoxia; may be delayed.
    • Management: oxygen, clinical assessment, CXR/POCUS; needle decompression/chest drain if tension/large symptomatic.
  • Vascular puncture/haematoma
    • Prevent with ultrasound, colour Doppler, aspiration, incremental injection; compress if superficial bleeding; seek senior help if expanding haematoma/anticoagulated.
  • Nerve injury
    • Avoid intraneural injection: do not inject against high resistance or with severe pain; keep needle tip in view; consider opening injection pressure monitoring if available.
    • Post-op: document neuro exam; reassure; early follow-up; refer to regional anaesthesia/nerve injury pathway if persistent deficits.
  • Infection (catheter)
    • Asepsis, secure dressing, daily review; remove if erythema, discharge, fever, unexplained pain.

Practical conduct, monitoring, and consent (FRCA-relevant)

  • Preparation
    • WHO sign-in, correct side marking, allergy check, anticoagulation status, baseline neuro exam (document).
    • Monitoring: ECG, NIBP, SpO2; IV access; resus drugs and lipid immediately available.
    • Sedation: titrate carefully; avoid oversedation (loss of feedback, airway obstruction).
  • Consent: key risks to mention
    • Failure/need for GA, bleeding/haematoma, infection, nerve injury, LAST, pneumothorax, vascular puncture, temporary weakness/numbness, falls risk.
    • Post-op advice: protect numb limb from heat/trauma; sling if needed; driving/work advice per local policy; when to seek help (persistent numbness/weakness, severe pain, SOB).
Describe the anatomy relevant to an infraclavicular brachial plexus block.

Aim: demonstrate you understand what you are blocking (cords), what you are not blocking (T2), and what you might hit (vessels/pleura).

  • At infraclavicular level the brachial plexus has formed cords around the axillary artery: lateral, posterior, medial.
  • Cords give rise to terminal nerves: musculocutaneous (from lateral cord), median (lateral+medial roots), ulnar (medial cord), radial (posterior cord), axillary (posterior cord).
  • Axillary vein is usually medial/anterior to artery; pleura lies deep/medial—source of pneumothorax risk.
  • Intercostobrachial nerve (T2) supplies medial upper arm and is not part of brachial plexus → tourniquet pain may persist.
What are the indications for an infraclavicular block and what surgery does it cover?

Answer in terms of region covered, advantages over other approaches, and limitations.

  • Anaesthesia/analgesia for surgery distal to mid-humerus: forearm, wrist, hand; elbow surgery often possible but tourniquet tolerance/coverage may be variable.
  • Useful when you want a dense distal block and a stable catheter site; often less risk of phrenic nerve palsy than interscalene/supraclavicular approaches.
  • Does not reliably cover intercostobrachial nerve (T2) → may need supplementation for tourniquet pain.
Outline how you would perform an ultrasound-guided infraclavicular block.

Structure: preparation → sonoanatomy → needle path → injection strategy → safety checks.

  • Preparation: consent, check anticoagulation, IV access, standard monitoring, full asepsis, lipid available; consider light sedation but maintain communication.
  • Probe: high-frequency linear (or curvilinear if deep); place inferior to clavicle near coracoid; identify axillary artery in short axis and cords around it; locate axillary vein with Doppler.
  • Needle: in-plane (commonly lateral-to-medial) with constant tip visualisation; avoid pleura by minimising deep/medial trajectory.
  • Injection: aspirate frequently; inject incrementally; aim for spread to cover posterior to artery (posterior cord) and achieve circumferential distribution (3–4 quadrants if needed).
  • Post-block: assess median/ulnar/radial/musculocutaneous sensory and motor function before incision; plan rescue if incomplete.
What local anaesthetic would you use, what volume, and how do you reduce the risk of LAST?

Examiners want safe dosing, incremental injection, and monitoring/management readiness.

  • Typical volume with ultrasound: 20–30 mL total (adjust to patient size, depth, and observed spread).
  • Choice depends on desired duration: ropivacaine/levobupivacaine for longer analgesia; lidocaine (often with adrenaline) for faster onset/shorter duration; follow local policy.
  • Reduce LAST risk: calculate max dose (mg/kg), use adrenaline as marker where appropriate, aspirate and inject in small aliquots, keep needle tip visible, avoid intravascular injection, monitor patient continuously.
  • Be prepared to treat LAST: stop injection, airway/oxygen/ventilation, seizure control, lipid emulsion per guideline, ALS modifications.
A patient complains of severe pain on injection during the block. What do you do and why?

This is a classic safety viva: recognise possible intraneural injection and act immediately.

  • Stop injecting immediately; do not “push through” resistance.
  • Reassess needle tip position on ultrasound; withdraw slightly and reassess; consider abandoning that trajectory.
  • Check injection pressure/resistance; high resistance and pain/paraesthesia suggest intraneural or fascicular injection risk → potential nerve injury.
  • Document event and post-block neuro status; ensure follow-up if symptoms persist.
What complications are specific or particularly relevant to infraclavicular block, and how would you recognise and manage them?

Cover pneumothorax, vascular puncture, LAST, nerve injury; include recognition and first-line management.

  • Pneumothorax: dyspnoea, pleuritic pain, hypoxia (may be delayed). Manage with oxygen, imaging/POCUS; treat tension pneumothorax immediately; chest drain if indicated.
  • Vascular puncture/haematoma: swelling/bruising, pain; prevent with Doppler and aspiration; manage with pressure and escalation if expanding/anticoagulated.
  • LAST: CNS symptoms → seizures/arrhythmias. Manage with airway/ventilation, benzodiazepines, lipid emulsion, ALS modifications.
  • Nerve injury: persistent sensory/motor deficit; avoid by tip visualisation and avoiding painful/high-pressure injection; document and follow nerve injury pathway if persistent.
Your infraclavicular block is patchy: radial nerve territory is spared. What is the likely cause and what are your options?

Common FRCA troubleshooting scenario: posterior cord not adequately covered.

  • Likely cause: inadequate LA spread posterior to the axillary artery → posterior cord (radial nerve) not blocked.
  • Options: targeted ultrasound-guided top-up posterior to artery (within safe dose), or perform a distal radial nerve block; consider GA if urgent or patient uncomfortable.
  • Reassess tourniquet plan and surgical site; ensure intercostobrachial nerve not the pain source.
How would you consent a patient for an infraclavicular block? What risks would you specifically mention?

Examiners want material risks, alternatives, and post-op advice.

  • Explain benefits: improved intra- and post-op analgesia, reduced opioids, possible avoidance of GA, ability to place catheter for prolonged pain relief.
  • Explain alternatives: GA, other brachial plexus approaches, surgeon infiltration, systemic analgesia.
  • Risks: failure/need for GA, bleeding/haematoma, infection, nerve injury (usually temporary, rarely permanent), vascular puncture, LAST, pneumothorax, temporary weakness/numbness and limb protection issues.
  • Post-op advice: protect numb limb, avoid heat/trauma, falls risk, when to seek help (persistent deficit, severe pain, shortness of breath).
Discuss infraclavicular block in an anticoagulated patient.

This is a common FRCA viva theme: apply principles and guidance rather than quoting numbers.

  • Infraclavicular block is a deep plexus block in a relatively non-compressible area; bleeding could be significant and difficult to control.
  • Follow current RA-UK/ASRA guidance for timing relative to anticoagulants/antiplatelets; assess drug, dose, renal function, and thrombotic risk; document shared decision-making.
  • If proceeding: meticulous ultrasound technique, minimise passes, consider smaller gauge needle, avoid vascular structures with Doppler, observe post-procedure for haematoma/neuro compromise.
  • If risk unacceptable: choose alternative analgesia (GA + multimodal, local infiltration, more superficial blocks where appropriate).

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