Abstract: Objective To explore the sedative effects of dexmedetomidine asa ward-based sedation on ventilated patients in intensive care unit. Methods Forty ventilated patients were divided into midazolam group(group A) and midazolam+ dexmedetomidine group(group B),with 20 patients in each group. Recorded the APACHE II score, Ramsay score and PaO2/FiO2 indicators before sedation. Heart rate, blood pressure and respiration were recorded at 4h, 6h and 12h of sedation. The infusion were ceased after 12h, then the sedative degree was assessed every 30 min, recover time, time to achieve satisfactory sedation and the sedation level were recorded. Results 90% of patients could achieve satisfactory sedation using dexmedetomidine alone, if the joint use of midazolam has only very low doses. The midazolam dosage, time to achieve satisfactory sedation and recover time in group B decreased significantly than those in Group A( P<0.05). Satisfactory degree of sedation in group B were higher than those in group A( P<0.05). Conclusion In medical ventilated patients, dexmedetomidine can improve the sedative efect of midazolam.

Key words: mechanical ventilation, sedation, midazolam, dexmedetomidine