Unilateral Epidural Block Cause — FRCA Final MCQ

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HardRegional AnaesthesiaUnilateral Epidural Block CauseFRCA Final

A thoracic epidural infusion develops unilateral block (right blocked, left not) on day 1. Most likely cause?

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Correct answer: A — Catheter too lateral in epidural space

Unilateral block most commonly = lateral catheter tip position pooling LA on one side. Management: withdraw 1-2 cm, re-bolus, position unblocked side dependent. Subdural = patchy unpredictable (not strictly unilateral). Nerve root sleeve = very localised dermatomal block.

Reference: RCOA – 2023 – Troubleshooting epidural analgesia