[Sedative effects of dexmedetomidine in post-operative elder patients on mechanical ventilation]

To evaluate the efficacy and safety of dexmedetomidine for post-operative elder patients on mechanical ventilation (MV).

For this randomized controlled trial, 108 cases of post-operative patients on MV were enrolled and assigned into either dexmedetomidine group (n = 54) or propofol group (n = 54) for sedation. And propofol was used for rescue. The dose of sedation was regulated by Ramsay score for maintaining a sedative score of 3-4. In both groups, fentanyl was provided intravenously continually for analgesia. The amount of fentanyl was adjusted according to the numerical rating scale (NRS) score for maintaining an analgesic score of 0-3. The average Ramsay score, the frequency of propofol, the highest score of NRS, the total dosage of fentanyl and recovery time were compared. Additional outcomes included duration of mechanical ventilation and intensive care unit (ICU) length. And the incidence of delirium and cardiovascular adverse events were compared for two groups.

No significant inter-group difference existed in the effectiveness of sedation. Compare with propofol group, the highest score of NRS decreased (1.8 ± 1.12 vs 3.1 ± 1.24, P < 0.05), the total dosage of fentanyl significantly decreased (427.6 ± 14.1 vs 658.4 ± 27.3 µg, P < 0.05) and recovery time became significantly shortened (0.3 ± 0.02 h vs 1.1 ± 0.3 h, P < 0.05) in dexmedetomidine group. Median duration of mechanical ventilation in dexmedetomidine group (21.0 h, 95%CI: 18.6-21.4 h) was significantly shorter than that in propofol group (28.0 h, 95%CI: 25.6-30.4 h) (P < 0.05). No inter-group differences existed in the ICU length of stay and the incidence of delirium. Two cases in dexmedetomidine group developed bradycardia while hypotension occurred in two cases of propofol group.

Sedative effects of dexmedetomidine are safe and effective for post-operative elder patients on MV. And it offers a better efficacy of analgesia and shorter durations of MV and recovery time. But dexmedetomidine had no significant influence on the ICU length of stay or the incidence of delirium.