Segmental distribution of high‐volume caudal anesthesia in neonates, infants, and toddlers as assessed by ultrasonography

Abstract

Background: The aim of this prospective, age‐stratified, observational study was to determine the cranial extent of spread of a large volume (1.5 ml·kg−1, ropivacaine 0.2%), single‐shot caudal epidural injection using real‐time ultrasonography. Methods: Fifty ASA I‐III children were included in the study, stratified in three age groups; neonates, infants (1–12 months), and toddlers (1–4 years). The caudal blocks were performed during ultrasonographic observation of the spread of local anesthetic (LA) in the epidural space. Results: A significant inverse relationship was found between age, weight, and height, and the maximal cranial level reached by 1.5 ml·kg−1 of LA. In neonates, 93% of the blocks reached a cranial level of ≥Th12 vs 73% and 25% in infants and toddlers, respectively. Based on our data, a predictive equation of segmental spread was generated: Dose (ml/spinal segment) = 0.1539·(BW in kg)–0.0937. Conclusions: This study found an inverse relationship between age, weight, and height and the number of segments covered by a caudal injection of 1.5 ml·kg−1 of ropivacaine 0.2% in children 0–4 years of age. However, the cranial spread of local anesthetics within the spinal canal as assessed by immediate ultrasound visualization was found to be in poor agreement with previously published predictive equations that are based on actual cutaneous dermatomal testing.

The location of paravertebral catheters placed using the landmark technique

“…Similar findings have been reported for single-injection paravertebral blocks [15] and for imaging studies in infants receiving caudal blocks [18,19]. The probable explanation for this is the time delay between the injection of the contrast dye and the subsequent local anaesthetic bolus injection and continuous infusion.…”

The European Society of Regional Anaesthesia and Pain Therapy/American Society of Regional Anesthesia and Pain Medicine Recommendations on Local Anesthetics and Adjuvants Dosage in Pediatric Regional Anesthesia

“…27 Some authors used more volume of diluted ropivacaine (0.15%): if the total dose is fixed, caudal analgesia with a larger volume of diluted ropivacaine provides better quality and longer duration after discharge than a smaller volume of more concentrated ropivacaine (0.125%). [28][29][30][31] In addition, ropivacaine undergoes slower systemic absorption from the caudal epidural space than bupivacaine; ropivacaine produces lower incidence of motor blockade in the early postoperative period than bupivacaine.…”

Evidence for the Use of Ultrasound Imaging in Pediatric Regional Anesthesia

“…A (prediction of epidural depth) Local anesthetic spread Brenner et al, 27 Lundblad et al, 35 Triffterer et al, 30 Tsui et al, 37 Ueda et al 39…”

“…27,30,35,37,39 Brenner et al 27 used ultrasound to show correlations between injectate volume (0.7, 1.0, or 1.3 mL/kg) and cranial spread during caudal blockade. There were significant positive correlations between 1.3 mL/kg and 0.7 mL/kg (P = 0.0002) as well as 1.3 mL/kg and 1.0 mL/kg (P = 0.03); however, the observed differences were small and did not allow for a reasonable prediction of a volume-cranial extension relationship.…”