To evaluate the efficacy of sedation with dexmedetomidine and midazolam or propofol combined with fentanyl for sedation in critically ill patients undergoing non-invasive ventilation.

Six-four patients scheduled for non-invasive ventilation in ICU were received sedation, who was divided into two groups: group Dex (n=41, sedated signally by dexmedetomidine) and group non-Dex (n=23, sedated by midazolam or propofol combined with fentanyl). A loading of dexmedetomidine 1 μg/kg followed by infusion lose at 0.2-0.5 μg/(kg?h), a loading of midazolam 0.05 mg/kg followed by infusion lose at 0.02-0.10 mg/(kg?h) and a loading of propofol 3 mg/kg followed by infusion lose at 0.5-3.0 mg/(kg?h). At the same time of administration of the midazolam and propofol, a loading dose of fentanyl 1 μg/kg was given, followed by fentanyl infusion at 1-2 μg/(kg?h). Ramsay Sedation Score (RSS) was recorded at baseline and 1, 12, and 24 hours after the loading dose was administered. And the following parameters were measured at baseline and 1, 12 and 24 hours: heart rate, blood pressure, respiratory rate and arterial blood gases. During the course, delirium, tracheal intubation, over-sedation, hypotension, hypertension, bradycardia were observed and registered continuously.

In both of the two groups patients, expected sedative scores were obtained. At 1 hour after the administration of drugs, RSS levels of group Dex and non-Dex were (2.3±0.5) scores vs (2.3±0.4) scores, t=0.00, P=1.000; at 12 hour were (2.3±0.5) scores vs (3.3±0.8) scores, t=6.16, P<0.001; at 24 hour were (2.4±0.5) scores vs (3.2±0.6) scores, t=5.71, P<0.001. Compared with the group non-Dex, the duration of ICU hospitalization in the group Dex were markedly decreased [(4.9±2.0) d vs (6.8±3.2) d, P=0.026]. In both groups, there was no significant difference in PaO₂/FiO₂, respiratory rate and mean blood pressure at different time point. The incidents of tracheal intubation, over-sedation, hypotension, hypertension, and bradycardia were not significantly different between the two groups. At one hour after the administration of drugs, the heart rates of group Dex and non-Dex were (78.4±17.6) times vs (93.3±25.0) times, t=2.79, P=0.007; at 12 hour were (77.1±10.7) times vs (86.5±13.4) times, t=3.08, P=0.003; at 24 hour were (71.4±6.9) times vs (80.9±14.3) times, t=3.59, P=0.001. The rate of delirium was significantly lower in group Dex (7.3% vs 39.1%, P<0.05). In subgroup analysis, compared to the patients without acute heart failure, the incident rate of hypotension in the patients with acute heart failure was significantly higher (group Dex, 71.4% vs 8.8%, P=0.001, group non-Dex, 66.7% vs 11.8%, P=0.008).

Sedative effects of both dexmedetomidine and midazolam or propofol combined with fentanyl are satisfactory for patients undergoing NIV. However, it is necessary to enhance observation to prevent and control hypotension in patients with acute heart failure.