OBJECTIVETo study whether hypoalbuminemia after pediatric cardiopulmonary bypass (CPB) for cardiac surgery is a risk factor for postoperative acute kidney injury (AKI).

METHODSA retrospective analysis was performed on the clinical data of 1 110 children who underwent CPB surgery between 2012 and 2016. According to the minimum serum albumin within 48 hours postoperatively, these patients were divided into hypoalbuminemia group (≤35 g/L) and normal albumin group (>35 g/L). The two groups were compared in terms of perioperative data and the incidence of AKI. Furthermore, the incidence of AKI was compared again after propensity score matching for the unbalanced factors during the perioperative period. The perioperative risk factors for postoperative AKI were analyzed by logistic regression.

RESULTSThe overall incidence rate of postoperative AKI was 13.78% (153/1 110), and the mortality rate was 2.52% (28/1 110). The mortality rate of children with AKI was 13.1% (20/153). The patients with hypoalbuminemia after surgery (≤35 g/L) accounted for 44.50% (494/1 110). Before and after propensity score matching, the hypoalbuminemia group had a significantly higher incidence of AKI than the normal albumin group (P<0.05). The children with AKI had a significantly lower serum albumin level after surgery than those without AKI (P<0.05). The multivariate logistic regression analysis showed albumin ≤35 g/L was one of the independent risk factors for postoperative AKI.

CONCLUSIONSAlbumin ≤35 g/L within 48 hours postoperatively is an independent risk factor for postoperative AKI in children after CPB surgery.