Paediatric regional anaesthesia: caudal block dosing and safety

Model answer

Anatomy/technique (4). Sacral hiatus anatomy including its relation to the dural sac, excluding occult dysraphism; asepsis and aspiration; ultrasound visualises the hiatus and local anaesthetic spread — preferred in infants.^[2]

Dosing (6). Armitage weight-based volumes (0.5/1.0/1.25 mL/kg); fluoroscopy shows 1.0 mL/kg spreads to median ~T12 with upper spread to T8: for T10-level analgesia in a 12 kg child, 1.25 mL/kg → 15 mL; at 0.25% that is 37.5 mg = 3.1 mg/kg, above the taught 2.5 mg/kg ceiling (confirm local formulary), so use a more dilute solution — state the mg/kg total and check it against the maximum before injecting.^[1]

LAST (5). Stop injection, call for help, ABCs, lipid emulsion rescue without delay, treat seizures, escalate refractory cases; small children carry higher LAST risk.^[3]