Spread of ropivacaine by a weight-based formula in a pediatric caudal block: a fluoroscopic examination

Area of Science:

• Pediatric Anesthesiology
• Regional Anesthesia
• Pharmacology

Background:

• Caudal block is a primary method for post-operative pain relief in pediatric infra-umbilical surgery.
• Determining the extent of spinal coverage with weight-based ropivacaine doses is crucial for effective analgesia.
• Fluoroscopic guidance aids in visualizing drug distribution within the extradural space.

Purpose of the Study:

• To ascertain the spinal segment coverage achieved by weight-based doses of 0.2% ropivacaine administered caudally in children.
• To evaluate the efficacy of ropivacaine for pediatric caudal blocks using fluoroscopic imaging.

Main Methods:

• A study involving 83 ASA I boys undergoing day-case urological surgery.
• Three dosage groups were established based on surgical site: 0.5 ml/kg (perineal), 1 ml/kg (inguinal hernia), and 1.25 ml/kg (orchiopexy).
• Ropivacaine mixed with radiopaque dye was injected caudally, and its spread was immediately assessed via fluoroscopy.

Main Results:

• The highest spinal levels reached were L2 (L4-T12) for 0.5 ml/kg, T12 (L1-T8) for 1 ml/kg, and T10 (L2-T7) for 1.25 ml/kg.
• A statistically significant wider spread of the anesthetic was observed in younger children (infants and toddlers) compared to older children.
• Fluoroscopic examination confirmed the extradural spread of ropivacaine in relation to injected volumes.

Conclusions:

• The weight-based dosages of ropivacaine, similar to those previously suggested for bupivacaine, effectively cover the required spinal levels for various pediatric infra-umbilical surgeries.
• Fluoroscopic findings support the use of established weight-based caudal ropivacaine doses for targeted surgical anesthesia in children.
• Age is a factor influencing the spread of caudal ropivacaine, with younger patients demonstrating greater cephalad distribution.