A2B (dexmedetomidine vs. propofol)
Trial question
What is the effect of dexmedetomidine-based sedation in critically ill patients on mechanical ventilation?
Study design
Multi-center
Open label
RCT
Population
Characteristics of study participants
36.0% female
64.0% male
N = 928
928 patients (333 female, 595 male).
Inclusion criteria: adult patients receiving mechanical ventilation in the ICU.
Key exclusion criteria: acute brain injury; neuromuscular paralysis; bradycardia; expected survival no longer than 24 hours.
Interventions
N=457 dexmedetomidine (starting dose 0.7 mcg/kg/h, maximum dose 1.4 mcg/kg/h).
N=471 propofol (no specific dose guidance given).
Primary outcome
Median time to successful extubation
136 hours
162 hours
162.0 hours
121.5 hours
81.0 hours
40.5 hours
0.0 hours
Dexmedetomidine
Propofol
No significant
difference ↔
No significant difference in median time to successful extubation (136 hours vs. 162 hours).
Secondary outcomes
No significant difference in death at day 180 (29% vs. 30%; HR 0.98, 95% CI 0.77 to 1.24).
No significant difference in time to first day with optimum sedation (3 days vs. 3 days; HR 0.94, 95% CI 0.83 to 1.07).
Safety outcomes
No significant difference in sedation-related adverse events.
Significant difference in severe bradycardia (33% vs. 20%).
Conclusion
In adult patients receiving mechanical ventilation in the ICU, dexmedetomidine was not superior to propofol with respect to median time to successful extubation.
Reference
Timothy S Walsh, Richard A Parker, Leanne M Aitken et al. Dexmedetomidine- or Clonidine-Based Sedation Compared With Propofol in Critically Ill Patients: The A2B Randomized Clinical Trial. JAMA. 2025 May 19:e257200. Online ahead of print.
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