Kellie Rodriguez, Rebecca L Anderson, Georgia Keriazes and Bruce Meyers
Introduction: Studies have demonstrated safety and efficacy of dexmedetomidine infusions at doses up to 1.5 mcg/kg/hr. Data evaluating doses greater than 1.5 mcg/kg/hr is limited; however, up to 2.5 mcg/kg/hr has been utilized. It is uncertain whether higher doses provide additional benefit but may result in more adverse events. The purpose of this study was to compare the safety and efficacy of dexmedetomidine at high doses (greater than 1.5 mcg/kg/hr) versus standard doses (0.2 to 1.5 mcg/kg/hr).
Methods: A retrospective cohort study was conducted in critically ill, mechanically ventilated patients receiving dexmedetomidine for at least 24 hours. Standard dose dexmedetomidine (SD-DEX) was defined as less than or equal to 1.5 mcg/kg/ hr and high dose (HD-DEX) as greater than 1.5 mcg/kg/hr. Patients were assigned to SD-DEX group if maximum dose of dexmedetomidine received was between 0.2 and 1.5 mcg/kg/hr. Conversely, patients were assigned to HD-DEX group if maximum dose of dexmedetomidine received was greater than 1.5 mcg/kg/hr. Composite incidence of bradycardia or hypotension and proportion of time within target sedation were assessed.
Results: A total of 799 patients were screened for inclusion with 120 included: 69 in the HD-DEX group and 51 in the SD-DEX group. Composite incidence of bradycardia or hypotension was not statistically different. A significantly larger proportion of time was spent within target sedation in the SD-DEX group. More patients in the HD-DEX group required sedatives and antipsychotics than the SDDEX group and tended to receive higher daily doses of concomitant medications.
Conclusion: Dexmedetomidine doses greater than 1.5 mcg/kg/hr may be as safe as standard doses; however, no additional benefit in maintaining target sedation level was found.
