Local Anaesthetic Toxicity — FRCA Final MCQ

Instant feedback + full explanation. One question, done properly.

ModerateRegional AnaesthesiaLocal Anaesthetic ToxicityFRCA Final

A 50-year-old woman weighing 70 kg (ASA II) has an adductor canal block with 20 mL of 0.5% bupivacaine. Immediately after injection she has a generalised seizure followed by pulseless cardiovascular collapse. Local anaesthetic systemic toxicity is diagnosed, CPR is commenced and oxygenation and ventilation are optimised. What initial intravenous bolus dose of 20% lipid emulsion should be given?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — 1.5 mL/kg bolus

Explanation lettering: C = shown as A · E = shown as B · D = shown as C · A = shown as D · B = shown as E

A is correct. UK Association of Anaesthetists guidance specifies an immediate intravenous bolus of 20% lipid emulsion 1.5 mL/kg over 1 minute, given alongside CPR and optimisation of oxygenation and ventilation. This is 105 mL for this patient, approximated to 100 mL in the adult algorithm. An infusion of 15 mL/kg/hour should also be started. The bolus may be repeated at 5 and 10 minutes if cardiovascular stability is not restored or subsequently deteriorates; the cumulative lipid-emulsion dose must not exceed 12 mL/kg. C is an underdose. B represents the initial dose plus one repeat bolus, not the initial bolus. D and E are several-fold greater than the recommended initial dose and would consume a substantial proportion of the cumulative maximum.

Reference: Association of Anaesthetists, Quick Reference Handbook 3-10: Local anaesthetic toxicity, 2018 — https://dev.rcoa.ac.uk/sites/default/files/documents/2019-11/QRH_3-10_Local_anaesthetic_toxicity_v1.pdf