重症的病人往往因潛在疾病、插管、臨床醫療處置以及睡眠被剝奪而容易躁動。導致躁動的原因包括焦慮、疼痛、瞻妄、呼吸困難以及神經肌肉阻斷劑所造成的麻痺，另外加護病房的病人因呼吸器設定不同的條件，需要將病人麻痺以配合呼吸器，鎮靜止痛藥物的使用目的主要為減少病人的不適與因呼吸器引起的傷害。使用鎮靜止痛藥物前，釐清躁動的原因與瞭解病人臨床狀況是很重要的。如何選擇藥物需依病人臨床狀況與潛在疾病來決定。現今有許多評估疼痛、躁動以及瞻妄的評估表可作為調整用藥的標準與深度。鎮靜深度須時時評估，再依病人的狀況來調整藥物。一旦臨床狀況改善可以試著調降鎮靜止痛藥物，調降藥物時須注意是否出現藥物戒斷現象，儘可能將鎮靜止痛藥物使用時間縮短。

Critically ill patients may distress due to underlying disease, intubation, procedure, and sleep deprivation. The etiologies of distress include anxiety, pain, delirium, dyspnea, and neuromuscular paralysis. The critically ill patients in intensive care unit (ICU) sometime need paralysis by ventilator setting. The goal of sedation-analgesics is to prevent patients from uncomfortable and ventilator related barotrauma. To identify the cause of distress and manage are important. The selection of the medication must be individualized according to the clinical condition and underlying diseases. There are many scoring systems for pain, agitation, and delirium. The goal depth of sedation should be reassessed and adjusted as the clinical situation. If clinical condition improved, then try to taper sedative-analgesic agents. Precaution drug withdrawal syndrome during taper medications. Sedative-analgesic medications should be used as shorter as possible.