Adjunctive dexmedetomidine therapy in the intensive care unit: a retrospective assessment of impact on sedative and analgesic requirements, levels of sedation and analgesia, and ventilatory and hemodynamic parameters.

STUDY
OBJECTIVE: To determine if adjunctive dexmedetomidine therapy in intensive care patients alters requirements for and levels of sedation and analgesia, and to describe hemodynamic and ventilatory parameters.
DESIGN: Retrospective, noncontrolled, descriptive study of clinical practice.
SETTING: Four intensive care units (ICUs; medical, surgical, neurosurgical, or burn) in a university-affiliated medical center. PATIENTS: Forty patients who were already receiving sustained use of propofol, lorazepam, or fentanyl when dexmedetomidine was started.
MEASUREMENTS AND MAIN RESULTS: Medical records were identified by searching the pharmacy database for patients who had received continuous-infusion dexmedetomidine from January 2000-January 2003 while in one of the four ICUs. Primary end points were discontinuation or dosage reduction of other sedatives or fentanyl from the hour before to 6 hours after starting dexmedetomidine. Other outcomes included levels of sedation and analgesia before and after dexmedetomidine and description of ventilatory and hemodynamic parameters. The initial dexmedetomidine rate of 0.4 +/- 0.25 microg/kg/hour changed minimally through 47.4 +/- 61.1 infusion hours. At 6 hours, 11 of 13 patients receiving propofol, 14 of 23 receiving lorazepam, and 4 of 30 receiving fentanyl had the respective agent discontinued. With dexmedetomidine, the hourly rates and cumulative daily doses were reduced only for propofol. Adequate sedation occurred at rates of 64.6% and 47.9% during the 24-hour periods before and after dexmedetomidine was started, respectively (p=0.001). Four and 12 patients had severe agitation before and after, respectively (p=0.05). One and 12 patients had severe pain before and after, respectively (p=0.02). Nine patients experienced hypotension or bradycardia. Twenty-two patients were successfully extubated within 24 hours of starting dexmedetomidine.
CONCLUSIONS: Adjunctive dexmedetomidine reduces sedative requirements but does not alter analgesic requirements. However, dexmedetomidine was associated with enhanced agitation, severe pain, and hemodynamic compromise. Transitioning to dexmedetomidine from other sedatives and analgesics may not provide optimal sedation and analgesia. Future studies are needed to evaluate dexmedetomidine as a bridge to extubation.