Differential effects of propofol and dexmedetomidine on explicit and implicit memory after sedation: a retrospective study

Objective To compare the effects of dexmedetomidine and propofol on early postoperative cognitive function and safety in patients undergoing short-term surgical sedation. Methods This retrospective cohort study included 295 adult patients who received intravenous sedation during non-cardiac surgery (January 2023–January 2025). Patients were divided into dexmedetomidine ( n = 150) and propofol ( n = 145) groups. Postoperative day 1 outcomes included explicit memory (RAVLT delayed recall) and processing speed (picture naming reaction time). Perioperative hemodynamics, recovery time, and adverse events were recorded. Results On postoperative day 1, the dexmedetomidine group showed higher RAVLT delayed recall scores (8.08 ± 3.06 vs. 7.24 ± 2.82, p = 0.015) but longer picture naming reaction time (881.42 ± 125.34 ms vs. 847.53 ± 118.76 ms, p = 0.037) compared to propofol. Median recovery time was longer with dexmedetomidine (18.00 vs. 14.00 min, p < 0.001). Dexmedetomidine was associated with more bradycardia requiring intervention ( p = 0.034), while propofol had more injection pain ( p < 0.001). No significant differences were found in hypoxemia or hypotension ( p > 0.05). Multivariate analysis identified dexmedetomidine use as an independent factor for higher postoperative RAVLT scores ( p = 0.007). Conclusion In this short-term sedation cohort, dexmedetomidine was associated with better explicit memory but slower processing speed and longer recovery versus propofol, with distinct safety profiles. The clinical significance of these small cognitive differences remains uncertain, and prospective validation is needed.