Paris Andrea, Kaufmann Markus, Tonner Peter H, Renz Philipp, Lemke Thees, Ledowski Thomas, Scholz Jens, Bein Berthold
Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Eur J Anaesthesiol. 2009 Jul;26(7):603-10. doi: 10.1097/EJA.0b013e32832a0c7c.
Alpha-2 agonists offer useful effects that make these drugs an interesting alternative for pharmacological premedication.
In a randomized, double-blind study, effects of clonidine (150 microg orally), midazolam (7.5 mg orally) and placebo administered 60-90 min prior to estimated anaesthesia induction time were investigated in 60 healthy ASA I or II patients. All patients received dipotassiumchlorazepate the evening before surgery. At predefined time points, effects of premedication on bispectral index, sedation score and visual analogue scales for anxiety and pain, cognitive function and stress hormones were determined.
Administration of low-dose clonidine was associated with slightly lower bispectral index scores than a standard dose of midazolam or placebo. There were no significant differences in sedation score, visual analogue scale for anxiety and pain and cognitive function between treatment regimens. Clonidine, but not midazolam, reduced anaesthetic requirements for induction of anaesthesia and prevented an increase in heart rate as well as an increase in adrenocorticotropic hormone plasma levels during the preoperative period (P < 0.05 vs. placebo). Clonidine administration did not delay postoperative recovery.
Clonidine augmented haemodynamic stability and partially blunted stress responses as determined by adrenocorticotropic hormone plasma levels. In addition, clonidine did not delay postoperative recovery. Therefore, surrogate parameters indicate that preanaesthetic medication with clonidine may be superior to midazolam in healthy individuals. Further studies have to confirm these results with regard to outcome parameters.
α₂ 激动剂具有有益作用，使其成为药理学术前用药的一个有趣选择。
在一项随机、双盲研究中，对 60 例健康的美国麻醉医师协会（ASA）I 或 II 级患者，于预计麻醉诱导时间前 60 - 90 分钟给予可乐定（口服 150 微克）、咪达唑仑（口服 7.5 毫克）和安慰剂，研究其效果。所有患者在手术前一晚服用氯氮䓬二钾。在预定时间点，测定术前用药对脑电双频指数、镇静评分、焦虑和疼痛视觉模拟量表、认知功能及应激激素的影响。
低剂量可乐定给药后，脑电双频指数评分略低于标准剂量咪达唑仑或安慰剂。各治疗方案之间在镇静评分、焦虑和疼痛视觉模拟量表及认知功能方面无显著差异。可乐定而非咪达唑仑降低了麻醉诱导所需麻醉药剂量，并防止术前心率增加以及促肾上腺皮质激素血浆水平升高（与安慰剂相比，P < 0.05）。给予可乐定未延迟术后恢复。
可乐定增强了血流动力学稳定性，并部分减轻了由促肾上腺皮质激素血浆水平所确定的应激反应。此外，可乐定未延迟术后恢复。因此，替代参数表明，在健康个体中，术前使用可乐定可能优于咪达唑仑。关于结局参数，还需进一步研究来证实这些结果。
