Maximum Volume of Local Anesthetic for Caudal Epidural Block
The maximum volume of local anesthetic that can be dosed in the caudal epidural space is 1.0 ml/kg for bupivacaine 0.25%, levobupivacaine 0.25%, or ropivacaine 0.2%, as recommended by the European Society for Paediatric Anaesthesiology (ESPA). 1
Local Anesthetic Options and Dosing
According to the 2024 ESPA pain management guidelines, the following are the recommended maximum volumes for caudal blocks:
- Bupivacaine 0.25%: 1.0 ml/kg
- Levobupivacaine 0.25%: 1.0 ml/kg
- Ropivacaine 0.2%: 1.0 ml/kg
These volumes can be supplemented with:
- Preservative-free clonidine (1-2 μg/kg) or
- Morphine (30-50 μg/kg) when adequate monitoring is available 1
Volume-Level Relationship
Recent research provides insights into the relationship between injection volume and spread of local anesthetic:
- A 2024 dynamic flow tracking study in pediatric patients aged 6-24 months found that the volume required to reach specific vertebral levels was 2:
- L5-S1: 0.125 ml/kg
- L4-L5: 0.223 ml/kg
- L3-L4: 0.381 ml/kg
- L2-L3: 0.591 ml/kg
- L1-L2: 0.797 ml/kg
- T12-L1: 0.960 ml/kg
- T11-T12: 1.050 ml/kg
This indicates that:
- 0.223 ml/kg may be sufficient for foot surgeries
- 0.591 ml/kg for knee surgeries
- 0.797 ml/kg for hip surgeries
Limitations and Considerations
A 2010 study showed that volumes between 0.5-1.0 ml/kg typically do not reliably spread higher than the L2 vertebral level in children aged 1-7 years 3
The spread of local anesthetic is not linear across different spinal levels, making precise prediction challenging 2
When higher levels of analgesia are required (e.g., for upper abdominal surgery), alternative approaches or formulas may be needed
Practical Application
- For lower extremity and perineal procedures: 0.5-1.0 ml/kg is typically sufficient
- For lower abdominal procedures: 0.75-1.0 ml/kg is recommended
- For higher abdominal procedures: Consider alternative approaches as caudal blocks with standard volumes may not reliably reach above L2
Monitoring Success
A decrease in heart rate (≥3 beats/min) during injection has been shown to be a reliable predictor of successful caudal block placement, with a sensitivity of 90.9% and specificity of 100% 4
Remember that while the maximum recommended volume is 1.0 ml/kg, the actual volume needed should be determined based on the required level of analgesia for the specific surgical procedure.