Ivani G, Bergendahl H T, Lampugnani E, Eksborg S, Jasonni V, Palm C, Mattioli G, Podesta E, Famularo A, Lönnqvist P A
Dept. of Anesthesiology, Gaslini Children's Hospital, Genua, Italy.
Acta Anaesthesiol Scand. 1998 Mar;42(3):306-11. doi: 10.1111/j.1399-6576.1998.tb04921.x.
The use of clonidine as an adjunct to epidural administration of local anesthetics in children has been reported to substantially improve the duration and quality of postoperative analgesia. The aims of the present study were to determine the pharmacokinetic profile and to investigate the interaction between postoperative sedation and analgesia after epidurally administered clonidine in children.
Plasma levels of clonidine (0-10 h postop) and assessment of postoperative analgesia and sedation (0-24 h postop) were performed at predetermined intervals following lumbar epidural administration of bupivacaine 2.0 mg/kg and clonidine 2 mg/kg in 8 children undergoing ureteral re-implantation surgery using general anesthesia (age range: 1-9 yr, weight range: 9-41 kg). Plasma levels of clonidine were analyzed by radioimmunoassay, and sedation and analgesia were assessed by previously described scoring systems.
The venous plasma pharmacokinetics of clonidine following epidural administration showed a considerable interindividual variation. Cmax and Tmax values of clonidine were found to be within the 0.45-0.77 ng/mL and 48-193 min range, respectively. The time to absorb 95% of the clonidine dose from the epidural space into plasma varied between 36 min and 7.6 h. In 6 of the 8 patients postoperative analgesia substantially outlasted the duration of sedation (> or = 2 h). Sedation could not be detected in any patients at plasma concentrations below 0.3 ng/mL.
The pharmacokinetic profile associated with epidural clonidine administration in children (1-9 y) was similar to that previously reported in adults. The postoperative analgesia seen after administration of epidural bupivacaine-clonidine during general anesthesia in children cannot only be explained by residual postoperative sedation.
据报道，可乐定作为儿童局部麻醉药硬膜外给药的辅助用药，可显著延长术后镇痛的持续时间并提高其质量。本研究的目的是确定可乐定的药代动力学特征，并研究儿童硬膜外给予可乐定后术后镇静与镇痛之间的相互作用。
对8例接受输尿管再植手术的儿童（年龄范围：1 - 9岁，体重范围：9 - 41 kg）在全身麻醉下进行腰段硬膜外给予布比卡因2.0 mg/kg和可乐定2 mg/kg后，按照预定时间间隔测定血浆可乐定水平（术后0 - 10小时），并评估术后镇痛和镇静情况（术后0 - 24小时）。采用放射免疫分析法分析血浆可乐定水平，通过先前描述的评分系统评估镇静和镇痛情况。
硬膜外给药后可乐定的静脉血浆药代动力学显示个体间存在相当大的差异。可乐定的Cmax和Tmax值分别在0.45 - 0.77 ng/mL和48 - 193分钟范围内。可乐定剂量从硬膜外腔吸收至血浆中95%的时间在36分钟至7.6小时之间变化。8例患者中有6例术后镇痛持续时间明显长于镇静持续时间（≥2小时）。血浆浓度低于0.3 ng/mL时，未在任何患者中检测到镇静作用。
1 - 9岁儿童硬膜外给予可乐定的药代动力学特征与先前在成人中报道的相似。儿童全身麻醉期间硬膜外给予布比卡因 - 可乐定后的术后镇痛不能仅用术后残留镇静来解释。
