Wang Fu, Qu Shijie, Chen Yinglu, Liao Bo, Ao Li, Zhang Hui, Zhou Hongyan, Zhang Liang
Department of Anesthesiology, Chongqing Traditional Chinese Medicine Hospital, Chongqing, China.
Department of Proctology, Chongqing Traditional Chinese Medicine Hospital, Chongqing, China.
Front Med (Lausanne). 2024 Nov 18;11:1481938. doi: 10.3389/fmed.2024.1481938. eCollection 2024.
Perineural administration of dexmedetomidine (PN-DEX) can enhance the efficacy of local anesthetics used in regional nerve blocks while decreasing the median effective concentration (EC50) of these anesthetics. Intranasal administration of dexmedetomidine (IN-DEX) is more accessible for sedation during regional anesthesia because of its non-invasive systemic administration and demonstrates synergism with local anesthetic. However, it remains unclear whether IN-DEX affects the EC50 of local anesthetics used in caudal blocks.
This study was a prospective, single-center, double-blind, randomized controlled trial. Patients scheduled to undergo elective hemorrhoidectomy were included and divided into three groups. Furthermore, 0.01 mL/kg of normal saline and 1 μg/kg and 2 μg/kg of dexmedetomidine were dripped into both nostrils of the patients in groups IN-NS, IN-DEX1, and IN-DEX2, respectively. These were administered 15 min before the caudal block. The initial concentration of ropivacaine was set at 0.4%, which was then varied by 0.025% using the up-and-down sequential allocation method. Vital signs, instances of hypotension and bradycardia with treatment, and other adverse reactions were recorded and compared.
The EC50 values of ropivacaine were 0.275% (95% confidence interval (CI), 0.254-0.296%) in group IN-NS, 0.257% (95% CI, 0.238-0.276%) in group IN-DEX1, and 0.216% (95% CI, 0.195-0.236%) in group IN-DEX2. The EC95 values of ropivacaine were 0.315% (95% CI, 0.295-0.370%) in group IN-NS, 0.297% (95% CI, 0.278-0.351%) in group IN-DEX1, and 0.256% (95% CI, 0.236-0.310%) in group IN-DEX2. Compared to group IN-NS, the EC50 value of ropivacaine in IN-DEX2 was significantly decreased by 21.4% ( = 0.001), while there was no significant difference between group IN-NS and IN-DEX1 ( = 0.125). There were no differences in hypotension and bradycardia with treatment among the different groups.
IN-DEX decreased the EC50 of ropivacaine for the caudal block, and there was a specific dose-dependent effect for IN-DEX. The side effects were similar across all groups.
右美托咪定神经周围给药（PN-DEX）可增强区域神经阻滞中使用的局部麻醉药的疗效，同时降低这些麻醉药的半数有效浓度（EC50）。右美托咪定鼻内给药（IN-DEX）因其非侵入性全身给药，在区域麻醉期间更容易用于镇静，并且与局部麻醉药表现出协同作用。然而，尚不清楚IN-DEX是否会影响骶管阻滞中使用的局部麻醉药的EC50。
本研究是一项前瞻性、单中心、双盲、随机对照试验。纳入计划接受择期痔切除术的患者，并将其分为三组。此外，分别向IN-NS组、IN-DEX1组和IN-DEX2组患者的双侧鼻孔滴注0.01 mL/kg生理盐水以及1 μg/kg和2 μg/kg右美托咪定。这些在骶管阻滞前15分钟给药。罗哌卡因的初始浓度设定为0.4%，然后使用上下顺序分配法以0.025%的幅度进行变化。记录并比较生命体征、治疗期间低血压和心动过缓的情况以及其他不良反应。
罗哌卡因的EC50值在IN-NS组为0.275%（95%置信区间（CI），0.254 - 0.296%），IN-DEX1组为0.257%（95% CI，0.238 - 0.276%），IN-DEX2组为0.216%（95% CI，0.195 - 0.236%）。罗哌卡因的EC95值在IN-NS组为0.315%（95% CI，0.295 - 0.370%），IN-DEX1组为0.297%（95% CI，0.278 - 0.351%），IN-DEX2组为0.256%（95% CI，0.236 - 0.310%）。与IN-NS组相比，IN-DEX2组罗哌卡因的EC50值显著降低了21.4%（P = 0.001），而IN-NS组和IN-DEX1组之间无显著差异（P = 0.125）。不同组之间治疗期间的低血压和心动过缓情况无差异。
IN-DEX降低了骶管阻滞中罗哌卡因的EC50，且IN-DEX存在特定的剂量依赖性效应。所有组的副作用相似。
