研究右美托咪定和咪达唑仑用于重症监护病房（ICU）机械通气（MV）患者的早期目标导向镇静的可行性及安全性。

选择2015年5月至2016年10月预计机械通气超过24 h且需要镇静的ICU患者80例，按随机数字表法分为2组，分别给予咪达唑仑（41例）和右美托咪定（39例）镇静治疗，根据镇静程度评估量表（RASS）评分调整镇静药剂量，使镇静深度评分控制在－2~＋1分；观察记录2组药物用量、48 h内浅镇静的时间、3 d内拔管率、两周内MV时间、ICU住院时间、ICU病死率以及心动过缓、谵妄、呼吸机相关性肺炎、物理约束、非计划拔管等的发生率。

右美托咪定与咪达唑仑均能使患者达到镇静目标评分，右美托咪定组更易达到浅镇静目标。与咪达唑仑组比较，右美托咪定组MV时间明显缩短[（102.47±81.84）h vs （172.71±83.09）h，P<0.05]，48 h内浅镇静的时间明显延长[（37.79±5.85）h vs （25.14±9.89）h，P<0.01]，3 d内拔管率明显增加（56.4% vs 24.4%，P<0.01），ICU住院时间明显缩短[（9.05±5.97）d vs （14.76±9.15）d，P<0.05]，谵妄发生率明显降低（30.8% vs 53.7%，P<0.05），但心动过缓发生率明显增加（33.3% vs 4.9%，P<0.01）。

与咪达唑仑治疗相比，以右美托咪定为基础的目标导向镇静方案具有良好的可行性及安全性，缩短了MV时间，提高了早期拔管率，缩短ICU住院时间，降低了谵妄发生率，但同时要加强心率的监测，防治心动过缓。

To assess the feasibility and safety of dexmedetomidine versus midazolam for early goal-directed sedation (EGDS) in patients undergoing mechanical ventilation (MV).

Eighty critically ill patients who were predicted to ventilate for > 24 hours were enrolled and randomly divided into two groups to receive either midazolam (41 cases) or dexmedetomidine (39 cases). In both groups, the dose of sedation was regulated according to the Richmond agitation sedation scale (RASS) to maintain the sedative score between -2 and 1. The amount of drug, duration of light sedation within 48 hours, extubation rate within three days, duration of MV within two weeks, length of ICU stay, ICU mortality, and the incidence of bradycardia, delirium, ventilator associated pneumonia, physical constraints, and unplanned extubation were recorded in the two groups.

In all the patients of the two groups taking dexmedetomidine or midazolam, expected sedative scores were achieved. Compared with the midazolam group, the patients in the dexmedetomidine group were easier to achieve light sedation and had significantly shorter duration of MV [(102.47±81.84) hours vs (172.71±83.09) hours, P<0.05], shorter length of ICU stay [(9.05±5.97) days vs (14.76±9.15) days, P<0.05], longer duration of light sedation within 48 hours [(37.79±5.85) hours vs (25.14±9.89) hours, P<0.01], higher rate of extubation within three days (56.4% vs 24.4%, P<0.01), lower rate of delirium (30.8% vs 53.7%, P<0.05), and higher rate of bradycardia (33.3% vs 4.9%, P<0.01).

Compared with midazolam, EGDS with dexmedetomidine is feasible and effective and can shorten the duration of MV and ICU stay, increase the rate of early extubation, and lower the rate of delirium. However, it is important to prevent and control bradycardia when dexmedetomidine is used.