Supraclavicular Block Pneumothorax — FRCA Final MCQ

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ModerateRegional AnaesthesiaSupraclavicular Block PneumothoraxFRCA Final

An adult receives an ultrasound-guided supraclavicular brachial plexus block. Within minutes, they develop sudden ipsilateral pleuritic chest pain, cough and dyspnoea. Their SpO2 falls to 90% on air, and breath sounds are reduced on the side of the block. Which complication is most likely?

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Correct answer: B — Pneumothorax

The correct answer is **A, pneumothorax**. The pleural dome lies close to the needle path during a supraclavicular block, so inadvertent pleural puncture remains possible despite ultrasound guidance. Sudden pleuritic pain, cough, hypoxaemia and unilateral reduction in breath sounds are characteristic. Phrenic nerve palsy causes ipsilateral hemidiaphragmatic paresis and may produce dyspnoea, but does not typically cause acute pleuritic pain or unilateral apical loss of breath sounds. Local anaesthetic systemic toxicity is suggested by circumoral paraesthesia, tinnitus, altered consciousness, seizures or cardiovascular instability. Haemothorax would usually require significant vascular injury and may cause haemodynamic deterioration. Horner syndrome causes ipsilateral ptosis, miosis and facial anhidrosis rather than pleuritic respiratory symptoms.

Reference: Gauss A, Tugtekin I, Georgieff M, et al. Incidence of clinically symptomatic pneumothorax in ultrasound-guided infraclavicular and supraclavicular brachial plexus block. Anaesthesia. 2014;69(4):327-336. https://pubmed.ncbi.nlm.nih.gov/24641639/