A new dosing protocol reduces dexmedetomidine-associated hypotension in critically ill surgical patients

Sedation with dexmedetomidine in the intensive care setting

Dexmedetomidine is an α-2 agonist that produces sedation and analgesia without compromising the respiratory drive. Use of dexmedetomidine as a sedative in the critically ill is associated with fewer opioid requirements compared with propofol and a similar time at goal sedation compared with benzodiazepines. Dexmedetomidine may produce negative hemodynamic effects including lower mean heart rates and potentially more bradycardia than other sedatives used in the critically ill. Recent studies have demonstrated that dexmedetomidine is safe at higher dosages, but more studies are needed to determine whether the efficacy of dexmedetomidine is dose dependent. In addition, further research is required to define dexmedetomidine’s role in the care of delirious critically ill patients, as many, but not all, studies have indicated favorable outcomes.

High-Dose Dexmedetomidine for Sedation in the Intensive Care Unit: An Evaluation of Clinical Efficacy and Safety

BACKGROUND:

Dexmedetomidine is an α2-receptor agonist used for sedation in the intensive care unit (ICU). Although dexmedetomidine is labeled for sedation in critically ill patients at doses up to 0.7 μg/kg/h, recent studies have used more liberal dosing regimens. However, to our knowledge, no study has assessed the clinical impact of doses greater than 0.7 μg/kg/h when compared to doses within the Food and Drug Administration-approved labeling.

OBJECTIVE:

To compare the clinical efficacy and safety of high (HD) and low (LD) dses of dexmedetomidine for sedation in the ICU.

METHODS:

This retrospective study included a sample of patients who received dexmedetomidine in medical, surgical, medical/surgical, and cardiothoracic ICUs between January 1, 2008, and December 1, 2009. Patients were included in the LD group if their maximum dose was less than 0.7 μg/kg/h or in the HD group if any dose was more than 0.7 μg/kg/h. Efficacy was determined by the percentage of Richmond Agitation and Sedation Scale (RASS) scores for each patient maintained at goal sedation (-1 to +1), and safety was determined by the incidence of hypotension and bradycardia.

RESULTS:

Forty-three of 133 patients received HD dexmedetomidine. Patients in the LD group had a significantly higher percentage of RASS scores at goal (60.0% vs 48.6%; p = 0.03), while those in the HD group experienced a higher percentage of RASS scores classified as undersedated (19.2% vs 4.9%; p = 0.001). There was no significant difference in the incidence of hypotension or bradycardia between groups.

CONCLUSIONS:

Patients treated with HD dexmedetomidine had fewer RASS scores at goal. Our data suggest that increasing the dose of dexmedetomidine may not enhance sedation efficacy or lead to an increased incidence of adverse effects. Patients who have not achieved goal sedation at doses of 0.7 μg/kg/h or less may not respond further to increased doses.

Review Article: Dexmedetomidine: Does it Have Potential in Palliative Medicine?

Dexmedetomidine, is a α 2 adrenergic agonist approved by the Food and Drug administration for sedation and analgesia. A highly potent α2 adrenergic agonist, it has quick onset of action, with peak effects within 1 hour of administration. It is metabolized in the liver and eliminated in the urine as a glucuronide. Dexmedetomidine is a substrate and inhibitor of cytochrome oxidase 2D6, but clinical evidence of significant drug interactions is lacking. Clinical trials suggest efficacy for the treatment of delirium in the intensive care unit setting with efficacy comparable to haloperidol and benzodiazepines. Dexmedetomidine also has an opioid-sparing action and can act to enhance analgesia. The purpose of this article is to review the pharmacodynamics and pharmacology of dexmedetomidine, and examine its potential use in the palliative care population, especially with regard to the management of delirium.