Abstract: Objective To compare the clinical outcomes of dexmedetomidine versus dexamethasone in combination with ropivacaine used for lumbar plexus block. Methods A total of 90 adult patients undergoing unilateral knee or thigh surgery were divided into 3 groups： Control, dexmedetomidine and dexamethasone （30 cases in each group）. All patients received posterior lumbar plexus block guided by ultrasound and nerve stimulator, during which ropivacaine 0.375% in the volume of 0.5 mL/kg was injected in the control group, and the equivalent anesthetic plus dexamethasone 0.1 mg/kg or dexmedetomidine 1 μg/kg was injected in the other two groups. The onset time and duration of sensory, motor block were compared among groups. The VAS pain scores, dosage of analgesics and incidence of complications were recorded after surgery. Results The onset time of sensory and motor block in the two experimental groups were faster than that of group Control （P<0.05）, and the duration of sensory and motor block in the two experimental groups were longer than that of group Control （P<0.05）, with significant difference between group dexmedetomidine and group dexamethasone. The VAS pain scores and dosage of analgesics in the two experimental groupswere lower than those of group Control （P<0.05）, with lower values in group dexmedetomidine than in group dexamethasone. There was no significant difference in complications among the three groups （P>0.05）. Conclusion While mixed with ropivacaine for lumbar plexus block, both dexmedetomidine and dexamethasone can accelerate onset time of block, prolong block duration and reduce postoperative pain, with better outcomes provided by dexmedetomidine thanby dexamethasone.

Key words: lumbar plexus block, ropivacaine, dexmedetomidine, dexamethasone

摘要： 目的 比较右美托咪定和地塞米松混合于罗哌卡因用于腰丛阻滞的临床效果。方法 选择单侧膝部或股骨手术的成年患者90例,ASAⅠ或Ⅱ级,随机分为三组：对照组、地米组和右美组,每组30例。三组患者均在超声联合神经刺激仪引导下行后路腰丛阻滞,对照组注入浓度为0.375%（3.75 mg/mL）的盐酸罗哌卡因0.5 mL/kg,地米组注入相同浓度、等效容量的局麻药和地塞米松0.1 mg/kg,右美组注入相同浓度、等效容量的局麻药和右美托咪定1 μg/kg。比较感觉、运动阻滞的起效时间和持续时间,记录术后24 h内VAS疼痛评分和镇痛药用量,观察并发症的发生情况。结果 感觉和运动阻滞的起效时间：右美组<地米组<对照组（P<0.05）;感觉和运动阻滞的持续时间：右美组>地米组>对照组（P<0.05）。地米组和右美组术后24 h的VAS疼痛评分低于对照组（P<0.05）;地米组和右美组术后24 h内的镇痛药用量少于对照组（P<0.05）,右美组少于地米组（P<0.05）。三组患者并发症的发生率无统计学差异。结论 右美托咪定或地塞米松与罗哌卡因混合应用均能加快腰丛阻滞的起效时间、延长持续时间和降低患者术后疼痛程度,但右美托咪定的作用更为显著。

关键词: 腰丛阻滞, 罗哌卡因, 右美托咪定, 地塞米松