Clinical Pearls & Morning Reports
Published June 26, 2019
Sedation is a component of the care of critically ill patients who are undergoing mechanical ventilation, but the appropriate choice of a primary sedative agent remains uncertain. The use of dexmedetomidine as the sole or primary sedative agent in patients undergoing mechanical ventilation has not been extensively studied. Shehabi et al. conducted a multinational, open-label, randomized, controlled trial to investigate the effect of using dexmedetomidine as the primary and, if possible, sole agent for early sedation among critically ill patients receiving ventilatory support. Read the Original Article here.
Q: What is the mechanism of action of dexmedetomidine?
A: Propofol and midazolam, which act mainly through pathways mediated by γ-aminobutyric acid, are widely used for sedation in critically ill patients who are undergoing mechanical ventilation. Dexmedetomidine, a high-affinity adrenergic agonist of the alpha2 receptor, is a potential alternative sedative.
Q: What benefits have been associated with the use of dexmedetomidine?
A: Dexmedetomidine induces sedation while preserving a degree of arousability among patients in the intensive care unit (ICU), and its use has resulted in a shorter time to extubation, an increased number of days free from coma or delirium, a reduced incidence of agitated delirium, prevention of delirium, and lower mortality than other agents administered in certain populations.
A: In the trial by Shehabi et al., among critically ill adults undergoing mechanical ventilation in the ICU, the early administration of dexmedetomidine as the sole or primary sedative did not result in lower 90-day mortality than usual care. In the modified intention-to-treat analysis, the primary outcome event of death from any cause at 90 days occurred in 566 of 1948 patients (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 [CI], −2.9 to 2.8; P=0.98). The between-group differences for secondary outcomes, including 180-day mortality and the percentage of institutionally dependent patients at 180 days, were not significant. Early in the course of the critical illness, most patients who were treated with dexmedetomidine received supplemental sedatives.
A: More adverse events and serious adverse events were reported in the dexmedetomidine group than in the usual-care group, most commonly bradycardia and hypotension, along with prolonged sinus arrest (asystole) (in 14 of 1954 patients [0.7%] and in 2 of 1964 patients [0.1%], respectively; P=0.003).