The effect of volume of local anaesthetic on the anatomical spread of caudal block in children age 1-7 years

Mark Thomas (1) , Richard Howard (2) , Claire Yule (3) , Derek Roebuck (4)

1 Anaesthesia
2 Department of Anaesthesia
3 Anaesthesia
4 Radiology

Objectives To examine the anatomical spread of caudal local anaesthetic solution in children age 1-7 years. Aim To determine whether incremental increases in the volume of caudal injections of 0.5, 0.75 and 1.0 ml/kg result in reliable (>90%) and potentially clinically significant increases in the number of vertebral segments reached. Background Caudal block is one of the most frequently performed paediatric regional analgesic techniques. Traditional formulae suggest that changes in the volume of caudal injectate in the range 0.5-1.0 ml/kg would have clinically useful effects. Methods In a single blind design, 45 children age 1-7 years undergoing caudal block received one of three pre-determined volumes (0.5, 0.75 and 1 ml/Kg) of local anaesthetic solution containing radio-opaque contrast under controlled conditions. Following X-ray examination, the anatomical spread of the block was reported by a radiologist blinded to the volume of solution received. Results There were 15 children in each group, they were similar in terms of age, height and weight. Spread was observed between the 5th Lumbar (L5) and 12th Thoracic (T12) vertebral levels. 1 ml/Kg results in a small but significantly greater spread of solution than 0.5 ml/Kg (p<0.05), but there was no difference between 0.5 and 0.75ml or between 0.75 and 1.0ml. No volume reliably reached a level higher than the second lumbar vertebra (L2). Conclusions Incrementally increasing the volume of injectate between 0.5 and 1.0 results in a modest increase in spread of the caudal solution. It is unlikely that volumes of less than 1ml will reliably reach a vertebral level that is higher than L2.

Mots clés: Medicine

Mark Thomas, Richard Howard, Claire Yule, Derek Roebuck. The effect of volume of local anaesthetic on the anatomical spread of caudal block in children age 1-7 years. Pediatric Anesthesia, 2010, 20 (11), pp.1017. ⟨10.1111/j.1460-9592.2010.03422.x⟩. ⟨hal-00587984⟩