ObjectivePostoperative atrial fibrillation, a prevalent complication following cardiac surgery, significantly increases patient morbidity and healthcare expenditures. Although dexmedetomidine has been proposed as a potential strategy to mitigate the risk of postoperative atrial fibrillation risk, existing evidence from randomized controlled trials has shown conflicting results.MethodsTo evaluate the efficacy of perioperative dexmedetomidine in adult cardiac surgery patients, we conducted a systematic search across four major electronic databases: (a) PubMed; (b) Embase; (c) the Cochrane Library; and (d) Web of Science. Our search sought all relevant randomized controlled trials on this specific intervention and patient population. We utilized random-effects models to synthesize treatment effects, expressed as risk ratios with 95% confidence intervals. Furthermore, trial sequential analysis and the Grading of Recommendations Assessment, Development, and Evaluation framework were applied to determine the robustness and certainty of the evidence, respectively.ResultsOur analysis included 22 randomized controlled trials, involving a total of 4063 patients. Dexmedetomidine administration significantly lowered the risk of postoperative atrial fibrillation risk compared with control groups (risk ratio 0.80, 95% confidence interval: 0.70-0.93; I2 = 28%). Subgroup analysis specifically indicated a significant reduction in postoperative atrial fibrillation risk in placebo-controlled trials, while no notable difference was observed when dexmedetomidine was compared with other active sedative agents. In addition, dexmedetomidine was associated with a reduced risk of postoperative delirium (risk ratio 0.62, 95% confidence interval: 0.44-0.87; I2 = 56%).ConclusionsPerioperative dexmedetomidine appears to reduce the risk of both postoperative atrial fibrillation risk and delirium in adult cardiac surgery patients, particularly compared with placebo. However, its efficacy relative to alternative active prophylactic agents remains unclear, necessitating rigorous comparative effectiveness trials.