METHODS: In an open-label, randomized trial, we enrolled critically ill adults who had been undergoing ventilation for less than 12 hours in the ICU and were expected to continue to receive ventilatory support for longer than the next calendar day to receive dexmedetomidine as the sole or primary sedative or to receive usual care (propofol, midazolam, or other sedatives). The target range of sedation-scores on the Richmond Agitation and Sedation Scale (which is scored from -5 [unresponsive] to +4 [combative]) was -2 to +1 (lightly sedated to restless). The primary outcome was the rate of death from any cause at 90 days.
RESULTS: We enrolled 4000 patients at a median interval of 4.6 hours between eligibility and randomization. In a modified intention-to-treat analysis involving 3904 patients, the primary outcome event occurred in 566 of 1948 (29.1%) in the dexmedetomidine group and in 569 of 1956 (29.1%) in the usual-care group (adjusted risk difference, 0.0 percentage points; 95% confidence interval, -2.9 to 2.8). An ancillary finding was that to achieve the prescribed level of sedation, patients in the dexmedetomidine group received supplemental propofol (64% of patients), midazolam (3%), or both (7%) during the first 2 days after randomization; in the usual-care group, these drugs were administered as primary sedatives in 60%, 12%, and 20% of the patients, respectively. Bradycardia and hypotension were more common in the dexmedetomidine group.
CONCLUSIONS: Among patients undergoing mechanical ventilation in the ICU, those who received early dexmedetomidine for sedation had a rate of death at 90 days similar to that in the usual-care group and required supplemental sedatives to achieve the prescribed level of sedation. More adverse events were reported in the dexmedetomidine group than in the usual-care group. (Funded by the National Health and Medical Research Council of Australia and others; SPICE III ClinicalTrials.gov number, NCT01728558.).
DESIGN: Randomized, prospective, double-blinded study.
SETTING: University-based tertiary referral center.
PATIENTS: Thirty claustrophobic adults with American Society of Anesthesiologists physical status I and II who were planned for MRI.
INTERVENTIONS: Patients were randomly assigned to target-controlled infusion propofol or dexmedetomidine loading followed by maintenance dose for procedural sedation.
MEASUREMENTS AND MAIN RESULTS: The primary end point was adequate reduction in patient anxiety levels to allow successful completion of the MRI sequence. Both methods of sedation adequately reduced anxiety levels in visual analog scale scores and Spielberger Strait Test Anxiety Inventory (Pbradycardia compared to none recorded in the propofol arm. There was no significant difference in patient satisfaction scores or home readiness after the MRI.
CONCLUSIONS: Both dexmedetomidine and propofol can effectively reduce anxiety levels of claustrophobic adults undergoing MRI, but dexmedetomidine takes longer to achieve adequate anxiolysis and sleep and may have an effect on image quality. Hypotension and bradycardia are common adverse effects observed with dexmedetomidine.