■最近的研究表明,右美托咪定可以安全地用于周围神经阻滞和脊髓麻醉。右美托咪定硬膜外给药产生镇痛和镇静,延长运动和感觉阻滞时间,延长术后镇痛,并减少对抢救镇痛的需要。本研究旨在确定罗哌卡因用于硬膜外运动阻滞的中位有效浓度(EC50)。并评估不同剂量的右美托咪定对EC50值的影响.
■预期,双盲,上下顺序分配研究。
■手术室,麻醉后监护病房,和一般的病房。
■将150名患者随机分为五组,双盲方式如下:NR(生理盐水联合罗哌卡因)组,RD0.25(0.25μg/kg右美托咪定联合罗哌卡因)组,RD0.5(0.5μg/kg右美托咪定联合罗哌卡因)组,RD0.75(0.75μg/kg右美托咪定联合罗哌卡因)组,RD1.0(1.0μg/kg右美托咪定联合罗哌卡因)组。每组首例患者的硬膜外罗哌卡因浓度为0.5%。在管理之后,立即将患者置于仰卧位进行观察,并且在给药后30分钟内使用改良的Bromage评分每5分钟评估下肢运动阻滞。根据顺序方法,根据前一位患者的反应调整下一位患者的罗哌卡因浓度:有效运动阻滞定义为硬膜外给药后30分钟内改良Bromage评分>0.如果前一位患者在给药后30分钟内的改良Bromage评分>0,下一位患者的罗哌卡因浓度下降1个梯度.相反,如果评分不超过0,则下一位患者的罗哌卡因浓度增加1个梯度.采用上下顺序分配法和probit回归法计算罗哌卡因硬膜外的EC50。
■不良事件,血液动力学变化,人口统计数据和临床特征。
■在NR组中,实现运动阻滞所需的硬膜外罗哌卡因的EC50为0.677%(95%CI,0.622-0.743%),RD0.25组中0.624%(95%CI,0.550-0.728%),RD0.5组中0.549%(95%CI,0.456-0.66%),RD0.75组中的0.463%(95%CI,0.408-0.527%),RD1.0组中为0.435%(95%CI,0.390-0.447%)。NR组和RD0.25组的EC50显著高于RD0.75组和RD1.0组,RD0.5组的EC50明显高于RD1.0组。
■在NR组中,实现运动阻滞所需的硬膜外罗哌卡因的EC50为0.677%,RD0.25组中的0.624%,RD0.5组中的0.549%,RD0.75组中的0.463%,RD1.0组为0.435%。右美托咪定作为罗哌卡因的佐剂,剂量依赖性地降低罗哌卡因硬膜外阻滞的EC50,缩短罗哌卡因硬膜外阻滞的起效时间。右美托咪定复合罗哌卡因用于硬膜外麻醉的最佳剂量为0.5μg/kg。
UNASSIGNED: Recent studies have shown that dexmedetomidine can be safely used in peripheral nerve blocks and spinal anesthesia.
Epidural administration of dexmedetomidine produces analgesia and sedation, prolongs motor and sensory block time, extends postoperative analgesia, and reduces the need for rescue analgesia. This investigation seeks to identify the median effective concentration (EC50) of ropivacaine for
epidural motor blockade, and assess how incorporating varying doses of dexmedetomidine impacts this EC50 value.
UNASSIGNED: Prospective, double-blind, up-down sequential allocation study.
UNASSIGNED: Operating room, post-anesthesia care unit, and general ward.
UNASSIGNED: One hundred and fifty patients were allocated into five groups in a randomized, double-blinded manner as follows: NR (normal saline combined with ropivacaine) group, RD0.25 (0.25 μg/kg dexmedetomidine combined with ropivacaine) group, RD0.5 (0.5 μg/kg dexmedetomidine combined with ropivacaine) group, RD0.75 (0.75 μg/kg dexmedetomidine combined with ropivacaine) group, RD1.0 (1.0 μg/kg dexmedetomidine combined with ropivacaine) group. The concentration of
epidural ropivacaine for the first patient in each group was 0.5%. Following administration, the patients were immediately placed in a supine position for observation, and the lower limb motor block was assessed every 5 min using the modified Bromage score within 30 min after drug administration. According to the sequential method, the concentration of ropivacaine in the next patient was adjusted according to the reaction of the previous patient: effective motor block was defined as the modified Bromage score > 0 within 30 min after epidural administration. If the modified Bromage score of the previous patient was >0 within 30 min after drug administration, the concentration of ropivacaine in the next patient was decreased by 1 gradient. Conversely, if the score did not exceed 0, the concentration of ropivacaine in the next patient was increased by 1 gradient. The up-down sequential allocation method and probit regression were used to calculate the EC50 of epidural ropivacaine.
UNASSIGNED: Adverse events, hemodynamic changes, demographic data and clinical characteristics.
UNASSIGNED: The EC50 of epidural ropivacaine required to achieve motor block was 0.677% (95% CI, 0.622-0.743%) in the NR group, 0.624% (95% CI, 0.550-0.728%) in the RD0.25 group, 0.549% (95% CI, 0.456-0.660%) in the RD0.5 group, 0.463% (95% CI, 0.408-0.527%) in the RD0.75 group, and 0.435% (95% CI, 0.390-0.447%) in the RD1.0 group. The EC50 of the NR group and the RD0.25 group were significantly higher than that of the RD0.75 and the RD1.0 groups, and the EC50 of the RD0.5 group was significantly higher than that of the RD1.0 group.
UNASSIGNED: The EC50 of epidural ropivacaine required to achieve motor block was 0.677% in the NR group, 0.624% in the RD0.25 group, 0.549% in the RD0.5 group, 0.463% in the RD0.75 group, and 0.435% in the RD1.0 group. Dexmedetomidine as an adjuvant for ropivacaine dose-dependently reduce the EC50 of epidural ropivacaine for motor block and shorten the onset time of
epidural ropivacaine block. The optimal dose of dexmedetomidine combined with ropivacaine for
epidural anesthesia was 0.5 μg/kg.