Department of Anesthesiology, Ningxia Medical University, Yinchuan, 750004, China.
Department of Anesthesiology, People's Hospital of Ningxia Hui Autonomous Region, Yinchuan, 750002, China.
BMC Anesthesiol. 2020 Apr 25;20(1):96. doi: 10.1186/s12871-020-01013-x.
The α-adrenergic agonist dexmedetomidine (DEX) is a sedative and can be used as an adjunct to hypnotics. The study sought to evaluate the effects of different doses of DEX on the requirements for propofol for loss of consciousness (LOC) in patients monitored via the bispectral index (BIS).
In this randomized, double-blind, three arm parallel group design and placebo-controlled trial, 73 patients aged between 18 and ~ 65 years with a BMI range of 18.0-24.5 kg·m and an American Society of Anesthesiologists (ASA) grade I or II who were scheduled for general anesthesia at the General Hospital of Ningxia Medical University were included in this study. Anesthesiologists and patients were blinded to the syringe contents. All patients were randomly assigned in a 1:1:1 ratio to receive a 0.5 μg·kg DEX infusion (0.5 μg·kg DEX group; n = 24), a 1.0 μg·kg DEX infusion (1.0 μg·kg DEX group; n = 25) or a saline infusion (control group; n = 24) for 10 min. Propofol at a concentration of 20 mg·kg·h was then infused at the end of the DEX or saline infusion. The propofol infusion was stopped when the patient being infused lost consciousness. The primary endpoint were propofol requirements for LOC and BIS value at LOC.
The data from 73 patients were analyzed. The propofol requirements for LOC was reduced in the DEX groups compared with the control group (1.12 ± 0.33 mg·kg for the 0.5 μg·kg DEX group vs. 1.79 ± 0.39 mg·kg for the control group; difference, 0.68 mg·kg [95% CI, 0.49 to 0.87]; P = 0.0001) (0.77 ± 0.27 mg·kg for the 1.0 μg·kg DEX group vs. 1.79 ± 0.39 mg·kg for the control group; difference, 1.02 mg·kg [95% CI, 0.84 to 1.21]; P = 0.0001). The propofol requirements for LOC was lower in the 1.0 μg·kg DEX group than the 0.5 μg·kg DEX group (0.77 ± 0.27 mg·kg vs. 1.12 ± 0.33 mg·kg, respectively; difference, 0.34 mg·kg [95% CI, 0.16 to 0.54]; P = 0.003). At the time of LOC, the BIS value was higher in the DEX groups than in the control group (67.5 ± 3.5 for group 0.5 μg·kg DEX vs. 60.5 ± 3.8 for the control group; difference, 7.04 [95% CI, 4.85 to 9.23]; P = 0.0001) (68.4 ± 4.1 for group 1.0 μg·kg DEX vs. 60.5 ± 3.8 for the control group; difference, 7.58 [95% CI, 5.41 to 9.75]; P = 0.0001).
The study showed that DEX (both 0.5 and 1.0 μg·kg DEX) reduced the propofol requirements for LOC. DEX pre-administration increased the BIS value for LOC induced by propofol.
The study was registered at ClinicalTrials.gov (trial ID: NCT02783846 on May 26, 2016).
α-肾上腺素能激动剂右美托咪定（DEX）是一种镇静剂，可作为催眠药物的辅助药物。本研究旨在评估不同剂量 DEX 对接受脑电双频指数（BIS）监测的患者异丙酚意识丧失（LOC）所需剂量的影响。
在这项随机、双盲、三臂平行组设计和安慰剂对照试验中，纳入了 73 名年龄在 18 至 65 岁之间、BMI 范围在 18.0-24.5kg·m 之间、ASA 分级 I 或 II 级、需要全身麻醉的宁夏医科大学总医院患者。麻醉师和患者对注射器内容物均不知情。所有患者按 1:1:1 的比例随机分为三组，分别接受 0.5μg·kg DEX 输注（0.5μg·kg DEX 组，n=24）、1.0μg·kg DEX 输注（1.0μg·kg DEX 组，n=25）或生理盐水输注（对照组，n=24），持续 10min。然后在 DEX 或生理盐水输注结束时输注浓度为 20mg·kg·h 的异丙酚。当输注的患者失去意识时，停止输注异丙酚。主要终点为 LOC 所需的异丙酚剂量和 LOC 时的 BIS 值。
对 73 名患者的数据进行了分析。DEX 组与对照组相比，LOC 所需的异丙酚剂量减少（0.5μg·kg DEX 组为 1.12±0.33mg·kg，对照组为 1.79±0.39mg·kg；差值，0.68mg·kg[95%CI，0.49 至 0.87]；P=0.0001）（1.0μg·kg DEX 组为 0.77±0.27mg·kg，对照组为 1.79±0.39mg·kg；差值，1.02mg·kg[95%CI，0.84 至 1.21]；P=0.0001）。1.0μg·kg DEX 组的 LOC 所需异丙酚剂量低于 0.5μg·kg DEX 组（0.77±0.27mg·kg 与 1.12±0.33mg·kg 相比；差值，0.34mg·kg[95%CI，0.16 至 0.54]；P=0.003）。在 LOC 时，DEX 组的 BIS 值高于对照组（0.5μg·kg DEX 组为 67.5±3.5，对照组为 60.5±3.8；差值，7.04[95%CI，4.85 至 9.23]；P=0.0001）（1.0μg·kg DEX 组为 68.4±4.1，对照组为 60.5±3.8；差值，7.58[95%CI，5.41 至 9.75]；P=0.0001）。
本研究表明，DEX（0.5 和 1.0μg·kg DEX）均降低了 LOC 所需的异丙酚剂量。DEX 预处理可增加异丙酚诱导 LOC 时的 BIS 值。
该研究在 ClinicalTrials.gov 注册（试验 ID：NCT02783846，于 2016 年 5 月 26 日）。
