Impact of Dexmedetomidine Dosing and Timing on Acute Kidney Injury and Renal Outcomes After Cardiac Surgery: A Meta-Analytic Approach.

Background: Acute kidney injury (AKI) is a common and serious complication following cardiac surgery. Dexmedetomidine, a highly selective α2-adrenergic agonist, has shown potential renoprotective effects, but previous studies have yielded conflicting results.

Objective: This meta-analysis aimed to evaluate the efficacy and safety of dexmedetomidine in preventing AKI and reducing postoperative serum creatinine levels in adult patients undergoing cardiac surgery.

Methods: We comprehensively searched 5 databases for randomized controlled trials comparing dexmedetomidine with control groups in adult cardiac surgery patients. The main outcomes were the incidence of AKI and change in postoperative serum creatinine levels. Meta-analyses were conducted using RevMan 5.4 models, and subgroup analyses were performed based on dexmedetomidine dosing and timing of administration. Continuous outcomes were combined and analyzed using either mean difference (M.D.), while dichotomous outcomes were analyzed using risk ratio (RR) with 95% confidence intervals (CI).

Results: Our study included a total of 14 trials involving 2744 patients. Dexmedetomidine administration significantly reduced the incidence of AKI compared to control groups (RR = 0.54, 95% CI: 0.41-0.70, P < 0.00001). Postoperative serum creatinine levels were also lower with dexmedetomidine (MD = -0.14 mg/dL, 95% CI: -0.28 to -0.001, P =0.04). Subgroup analyses revealed that higher initial doses (>0.5 μg/kg) and administration during intraoperative and postoperative periods were associated with more pronounced renoprotective effects. Dexmedetomidine did not significantly affect mortality but reduced the duration of the length of hospital stay and mechanical ventilation.

Conclusions and relevance: This meta-analysis demonstrates that dexmedetomidine administration, particularly at higher doses and during both intraoperative and postoperative periods, reduces the risk of AKI in adults undergoing cardiac surgery. These findings support the use of dexmedetomidine as a preventive strategy to enhance renal outcomes in this population.