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.