指对右美托咪啶还是整个镇静剂？

Sedation 

Another focus of the ICU Liberation bundle is the choice of sedative [2]. The recent critical care guidelines to decrease use of benzodiazepines for sedation has led to an increased use of dexmedetomidine and ketamine infusions. Ketamine in particular has had increased rates of use because of its favorable hemodynamic profile. However, a recent meta-analysis highlights the overall lack of data to guide its optimal use. Ketamine did not decrease opioid use, ventilator days, or ICU lengths of stay, yet was associated with decreased incidence of delirium [12 &]. Although dexmedetomidine is often used for sedation, it has not been rigorously studied as a primary sedative agent in the ICU. Dexmedetomidine has several potential benefits including lack of respiratory depression, anxiolytic effects, and potential opioid-sparing effects [13]. Most of the literature on dexmedetomidine focuses on the perioperative setting. A recent randomized trial highlighted just how much is unknown. Patients receiving dexmedetomidine titrated for a goal sedation score of RASS -2 to +1 experienced more hypotension and bradycardia and required more adjunct sedatives than those in the usual care group [14 &]. More studies are needed to investigate effects on agitation, analgesic and sedation requirements, and potential adverse effects including hypotension and delirium.

镇静

ICU解放集束化措施的另一个焦点是镇静剂的选择。最近的重症监护指南减少了苯二氮卓类药物用于镇静的使用，导致右旋美托咪啶和氯胺酮输注的使用增加。尤其是氯胺酮，由于其良好的血流动力学特征，使用率有所增加。然而，最近的一项荟萃分析强调了总体上缺乏数据来指导其最佳使用。氯胺酮不会减少阿片类药物的使用、呼吸机天数或ICU住院时间，但与减少谵妄的发生率有关。虽然右美托咪啶经常用于镇静，但在ICU中作为主要镇静剂还没有得到严格的研究。右美托咪啶有几个潜在的好处，包括无呼吸抑制、抗焦虑、以及潜在的阿片类药物的节省效果。大多数关于右美托咪啶的文献都集中在围手术期的应用上。最近的一项随机试验就强调了对右美托咪啶有太多的未知。接受右美托咪啶滴定，目标镇静评分RASS-2到+1的患者，与常规治疗组相比，出现更多的低血压和心动过缓，需要更多的辅助镇静剂。需要更多的研究来研究对躁动、镇痛和镇静需求的影响，以及包括对低血压和谵妄在内的潜在不良反应。

how much is unknown.有太多的未知   这么理解对吗？

More studies are needed to investigate effects on agitation, analgesic and sedation requirements, and potential adverse effects including hypotension and delirium.指对右美托咪啶还是整个镇静剂？