Bradycardia during dexmedetomidine and therapeutic hypothermia

Dexmedetomidine is a centrally acting alpha2-adrenergic agonist which is currently Food and Drug Administration-approved for the short-term (less than 24 hours) sedation of adults during mechanical ventilation. Given its beneficial physiologic effects and limited adverse effect profile, there is growing interest regarding its potential applications in the Pediatric intensive care unit patient including sedation during mechanical ventilation, procedural sedation, the treatment of withdrawal, and prevention of emergence agitation. Although generally safe and effective, occasional hemodynamic effects including bradycardia and hypotension have been reported. Clinical experience has demonstrated that bradycardia may be more common when dexmedetomidine is administered with other medications that have negative chronotropic effects. We report 2 pediatric patients with traumatic brain injury who had good long-term neurologic outcomes, but developed clinically significant bradycardia when therapeutic hypothermia was added to a sedation regimen that included dexmedetomidine and remifentanil. The role of dexmedetomidine as a neuroprotective agent is explored as well as a review presented of previous reports of bradycardia related to dexmedetomidine.