Infraclavicular block

11 min read Last updated April 9, 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.
  • 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).

Test yourself…

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).

0 comments