Impact of dexmedetomidine administration on mortality in patients with cardiac arrest: a propensity score matching analysis of the MIMIC-IV database.

Dexmedetomidine (DEX), a selective α2-adrenoceptor agonist, is used in critical care for sedation and sympathetic modulation. However, its association with survival after cardiac arrest remains uncertain.This study investigated the relationship between DEX administration and mortality risk in cardiac arrest patients.This retrospective cohort study utilized the MIMIC-IV database. Adult patients with documented cardiac arrest (as defined by ICD-9/10 codes) prior to intensive care unit (ICU) admission were stratified into DEX-exposed and unexposed groups based on dexmedetomidine administration. The primary outcome was 28-day mortality; secondary endpoints were 90-day and 1-year mortality. Patients were matched 1:1 using propensity score matching (PSM) based on key baseline characteristics such as demographics, comorbidities, and illness severity scores to minimize confounding. Robustness was assessed through sensitivity analyses and adjusted multivariable Cox regression. Among 1,342 patients, 314 (23.4%) received DEX. After PSM (269 matched pairs), DEX exposure were associated with significantly lower mortality rates at 28 days (90/269 [33.5%] vs. 150/269 [55.8%]), 90 days (112/269 [41.6%] vs. 165/269 [61.3%]), and 1 year (128/269 [47.6%] vs. 180/269 [66.9%]). Multivariable analysis showed DEX administration was independently associated with lower mortality at 28-day (HR 0.36, 95% CI 0.27-0.48, p < 0.001), 90-day (HR 0.42, 95% CI 0.32-0.54, p < 0.001), and 1-year (HR 0.44, 95% CI 0.34-0.56, p < 0.001). These associations remained consistent across sensitivity analyses and subgroups stratified by gender, age, comorbidity burden, and illness severity scores. DEX administration demonstrated a significant association with improved survival in post-cardiac arrest patients, suggesting a potential role in post-cardiac arrest management. Prospective studies are warranted to confirm its clinical efficacy and safety in post-arrest management.