Spread of ropivacaine by a weight-based formula in a pediatric caudal block: a fluoroscopic examination.
BACKGROUND
Caudal block is the most common regional technique to provide post-operative analgesia in pediatric infra-umbilical surgery. This study was designed to define how many spinal segments would be covered by the weight-based dosage of caudally administered 0.2% ropivacaine in children using the fluoroscopic method.


METHODS
After an approval from the institutional human research review board, in 83 ASA I boys undergoing day-case urological surgery, the distribution of ropivacaine mixed with a radioactive dye in relation to the volume injected caudally was studied. Three groups were studied: for perineal surgery 0.5 ml/kg (group C(0.5)), for inguinal hernia repair 1 ml/kg (group C(1.0)), and for orchiopexy 1.25 ml/kg (group C(1.25)). The dose of 0.2% ropivacaine containing radiopaque dye at a ratio of 1 : 4 was injected at a rate of 1 ml 3 s(-1). Fluoroscopic examination was performed immediately to define the level of the drug spread within the extradural space.


RESULTS
The highest spinal levels [median with ranges] of spread were L2 [L4-T12] in group C(0.5), T12 [L1-T8] in group C(1.0), and T10 [L2-T7] in group C(1.25). Analysis by age distribution (infants: <12 months; toddlers: 12-36 months; and children: >36 months) revealed a larger spread in younger patients.


CONCLUSIONS
Based on the fluoroscopic findings, the weight-based doses for caudally administered 0.2% bupivacaine suggested by Armitage are also useful for ropivacaine to block the spinal level required for the different types of surgeries studied.
Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
B-N
BN
Koo
J-Y
JY
Hong
H K
HK
Kil
D000577:Amides / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000763:Anesthesia, Caudal / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001835:Body Weight; D002675:Child, Preschool; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D004339:Drug Compounding; D005471:Fluoroscopy; D006552:Hernia, Inguinal / Q000601:surgery; D006801:Humans; D007223:Infant; D008161:Lumbosacral Region / Q000000981:diagnostic imaging; D008297:Male; D009407:Nerve Block / Q000379:methods; D056126:Orchiopexy; D000077212:Ropivacaine; D013116:Spinal Cord / Q000000981:diagnostic imaging* / Q000378:metabolism
D000577:Amides; D000779:Anesthetics, Local; D003287:Contrast Media; D000077212:Ropivacaine