Caudal Epidural in Children — FRCA Final MCQ

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ModeratePaediatric AnaesthesiaCaudal Epidural in ChildrenFRCA Final

A 3-year-old child weighing 15 kg is undergoing inguinal hernia repair. You plan a single-shot caudal epidural block for postoperative analgesia. Using the traditional Armitage weight-based volume scheme, with the local-anaesthetic concentration selected separately to keep the total dose within an appropriate limit, which injectate volume corresponds to sacral-to-low-thoracic spread?

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Correct answer: A — 1.25 mL/kg

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

C is correct. In the traditional Armitage weight-based scheme, 0.5 mL/kg is used for predominantly sacral spread, 1.0 mL/kg for lumbar spread and 1.25 mL/kg for low-thoracic spread. Fluoroscopic evidence found median spread to T10 with 1.25 mL/kg, compared with T12 after 1.0 mL/kg. For this 15 kg child, the corresponding total volume is 18.75 mL. Options D and E are not standard Armitage categories and increase the risk of excessive cephalad spread. Importantly, injectate volume determines spread but must not be confused with drug dose: the concentration must be adjusted independently. The original combination of 1.25 mL/kg and 0.25% levobupivacaine would deliver 3.125 mg/kg, which is not supported by the cited UK paediatric study or the current SmPC.

Reference: Hong JY et al. Spread of ropivacaine by a weight-based formula in a pediatric caudal block: a fluoroscopic examination. Acta Anaesthesiologica Scandinavica. 2010. https://pubmed.ncbi.nlm.nih.gov/20236099/