Radiographic Observation Of Local Anesthetic Spread In Caudal-epidural Space Of Children

Objective: Through the X-ray imaging technology to observe the spreadof caudally administered local anesthetic within pediatric caudal-epiduralspace. To discuss the medication characteristics of pediatric caudal block.Methods: Forty-five children,ASAⅠ~Ⅱ,aged8~51months and weight-ing9~20kg, undergoing inguinal hernia repair or pediatric lower limborthopedic surgery received caudal block were included in thisrandomized,observer-blinded clinical trial.children were divided into threegroups by caudal injection capacity: group A (0.5ml·kg-1), group B(0.75ml·kg-1) and group C (1ml·kg-1),15patients in each group.The mixtureof0.75%ropivacaine and iohexol formulated by1:2proportions was injectedinto caudal-epidural space at a rate of0.5ml·s-1.Following X-ray examinationafter5minutes,the imaging of spread,the total radiographic lengths of spreadand the covered numbers of vertebral segment of the local anesthetic withinthe caudal-epidural space were reported by a radiologist.Then calculate thehighest vertebral segment of cranial spread of the local anesthetic within thecaudal-epidural space. In order to investigate possible age-dependentdifferences in the cranial spread of the local anesthetic,all three groups werepooled and divided by age (≤12months,>12~36months and>36months).Calculate the covered numbers of vertebral segment of the local anestheticand the milliliter of local anesthetic required for per vertebral segment in eachmonths group.Results: There were no statistically significant differences in patients’age,weight and height between Group A,B and C (P>0.05). The mean±SD oftotal radiographic length of the local anesthetic within the caudal-epiduralspace in Group A, B, and C were13.25±2.28cm,16.30±1.88cm and18.42±1.32cm, respectively. Statistically significant differences were found between Group A, B and C (P <0.05). The median (interquartile range) ofcovered numbers of vertebral segment of the local anesthetic within thecaudal-epidural space in Group A, B, and C were9(1),10(1) and12(1),respectively. Statistically significant differences were found between GroupA,B and C (P <0.05). The median (range) of highest vertebral segment ofcranial spread of the local anesthetic within the caudal-epidural space inGroup A, B, and C were L3(L4~L2), L2(L3~T12),and T12(L2~T11),respectively. Statistically significant differences were found between GroupA,B and C (P <0.05). The mean±SD of milliliter of local anesthetic requiredfor per vertebral segment in Months≤12,>12~36and>36were0.64±0.11ml,0.93±0.19ml and1.22±0.24ml, respectively. Statistically significantdifferences were found between Months≤12,>12~36and>36(P <0.05).Conclusion:1. There was numerically small correlation betweenincreased injected volumes of local anesthetic and the spread of caudallyadministered local anesthetic.2. Younger children had a significantly widerspread with the same weight-based volume of local anesthetic.