She Ying-Jun, Zhang Zhi-Yi, Song Xing-Rong
Department of Anesthesiology, Guangzhou Women and Children Medical Center, Guangzhou Medical University affiliated Women and Children Medical Center, Guangzhou, China.
Paediatr Anaesth. 2013 Dec;23(12):1205-12. doi: 10.1111/pan.12278. Epub 2013 Oct 12.
Dexmedetomidine (D) can prolong the duration of local anesthetics, but the effect of caudal dexmedetomidine on the potency of levobupivacaine (L) for caudal block has not been investigated. This study was designed to determine the effect of caudal dexmedetomidine on levobupivacaine for caudal block in pediatric patients.
Eighty-nine children scheduled for elective inguinal hernia repair or hydrocele were randomly assigned to one of the three groups: Group L (caudal levobupivacaine), Group LD1 (levobupivacaine plus 1 μg·kg(-1) dexmedetomidine), or Group LD2 (levobupivacaine plus 2 μg·kg(-1) dexmedetomidine). The primary endpoint was the minimum local anesthetic concentration (MLAC), which was determined using the Dixon up-and-down method. The secondary endpoints were the duration of analgesia and sedation.
The MLAC values (sd) of caudal levobupivacaine were 0.103 (0.01)%, 0.068 (0.02)%, and 0.055 (0.03)% in Groups L, LD1, and LD2, respectively. The values of EC50 and EC95 (95% CI) of caudal levobupivacaine from logistic regression analysis were 0.094 (0.083-0.105)% and 0.129 (0.1-0.159)%, 0.058 (0.044-0.072)% and 0.106 (0.067-0.144)%, and 0.046 (0.033-0.059)% and 0.091 (0.055-0.127)% in Groups L, LD1, and LD2, respectively. The mean durations of analgesia in the postoperative period were 141, 378, and 412 min in Groups L, LD1, and LD2, respectively (L vs LD1 or LD2, P < 0.001). The mean durations of sedation in both Groups LD1 and LD2 also were significantly prolonged, compared with Group L (P < 0.01).
Caudal dexmedetomidine reduces the MLAC values of levobupivacaine and improves postoperative analgesia in children without any neurological side effects.
右美托咪定（D）可延长局部麻醉药的作用时间，但骶管内注入右美托咪定对左旋布比卡因（L）用于骶管阻滞时药效的影响尚未得到研究。本研究旨在确定骶管内注入右美托咪定对小儿患者左旋布比卡因用于骶管阻滞的影响。
89例计划行择期腹股沟疝修补术或鞘膜积液手术的儿童被随机分为三组之一：L组（骶管内注入左旋布比卡因）、LD1组（左旋布比卡因加1μg·kg⁻¹右美托咪定）或LD2组（左旋布比卡因加2μg·kg⁻¹右美托咪定）。主要终点是最低局部麻醉药浓度（MLAC），采用Dixon上下法测定。次要终点是镇痛和镇静持续时间。
L组、LD1组和LD2组骶管内左旋布比卡因的MLAC值（标准差）分别为0.103（0.01）%、0.068（0.02）%和0.055（0.03）%。根据逻辑回归分析，L组、LD1组和LD2组骶管内左旋布比卡因的EC50和EC95（95%可信区间）值分别为0.094（0.083 - 0.105）%和0.129（0.1 - 0.159）%、0.058（0.044 - 0.072）%和0.106（0.067 - 0.144）%、0.046（0.033 - 0.059）%和0.091（0.055 - 0.127）%。术后L组、LD1组和LD2组的平均镇痛持续时间分别为141、378和412分钟（L组与LD1组或LD2组比较，P < 0.001）。与L组相比，LD1组和LD2组的平均镇静持续时间也显著延长（P < 0.01）。
骶管内注入右美托咪定可降低左旋布比卡因的MLAC值，并改善小儿术后镇痛，且无任何神经方面的副作用。
