Background: Dexmedetomidine has been reported to have a renal protective effect after adult open heart surgery. The authors prospectively investigated the effect of intraoperative dexmedetomidine on acute kidney injury (AKI) after paediatric congenital heart surgery with cardiopulmonary bypass. 
Methods: Twenty-nine paediatric patients (1-6 yrs) scheduled for atrial or ventricular septal defect repair were randomly assigned to receive either continuous infusion of normal saline (control group, n=14) or dexmedetomidine (a bolus dose of 0.5 µg/kg and then an infusion of 0.5 µg/kg/h) (dexmedetomidine group, n=15) after anaesthetic induction until cardiopulmonary bypass weaning. Serum creatinine (Scr) was measured before surgery (T0), 10 min after anaesthesia induction (T1), 5 min after cardiopulmonary bypass weaning (T2), 2 hours after T2 (T3), and after postoperative day 1 (POD1) and postoperative day 2 (POD2) and estimated glomerular filtration rates (eGFRs) were calculated. Renal biomarkers were measured at T1, T2 and T3. AKI was defined as an absolute increase in Scr of  ≥ 0.3 mg/dl or a percent increase in Scr  of ≥ 50%.
Results: The incidence of AKI during the perioperative period was significantly higher in the control group than in the dexmedetomidine group (64% (9/14) vs. 27% (4/15), P = 0.042). eGFR was significantly lower in the control group than in the dexmedetomidine group at T2 (72.6 ± 15.1 vs. 83.9 ± 13.5, P = 0.044) and T3 (73.4 ± 15.4 vs. 86.7 ± 15.9, P = 0.03). eGFR decreased significantly at T2, T3, and T4 (P < 0.001, < 0.001 and 0.009, respectively) as compared with T0, in the control group and at T2 and T3 (P values < 0.001) in the dexmedetomidine group. Renal failure indices, fractional excretions of sodium (FENa), urine N-acetyl-beta-D-glucosaminidase to creatinine ratios (UNAG/Ucr), and urine microalbumin to creatinine ratios (UAlb/Ucr) at T1, T2 and T3 and changes in these variables over time were not significantly different in the groups. 
Conclusions: Intraoperative infusion of dexmedetomidine might reduce the incidence of AKI and suppress post-bypass eGFR decline, but was not found to improve other renal biomarkers after paediatric open heart surgery.

The effect of intraoperative dexmedetomidine on acute kidney injury after paediatric congenital heart surgery