OBJECTIVETo study the association between fluid overload and acute kidney injury (AKI) after congenital heart disease surgery in infants.

METHODSA retrospective analysis was performed on 88 infants aged less than 6 months who underwent a radical surgery for congenital heart disease. The treatment outcomes were compared between the infants with AKI after surgery and those without. The effect of cumulative fluid overload on treatment outcomes 2 days after surgery was analyzed. The risk factors for the development of AKI after surgery were assessed by logistic regression analysis.

RESULTSCompared with those without AKI after surgery, the patients with AKI had younger age, lower body weights, higher serum creatinine levels and higher vasoactive-inotropic score, as well as longer durations of intraoperative extracorporeal circulation and aortic occlusion (P<0.05). Compared with those without AKI after surgery, the patients with AKI had a higher transfusion volume, a higher incidence rate of low cardiac output syndrome, a longer duration of mechanical ventilation, a longer length of stay in the intensive care unit (ICU), a longer length of hospital stay, a higher application rate of extracorporeal membrane oxygenation, a higher 30-day mortality rate, and higher levels of cumulative fluid overload 2 and 3 days after surgery (P<0.05). The logistic regression analysis showed that fluid overload and low cardiac output syndrome were major risk factors for the development of AKI after surgery. The children with cumulative fluid overload >5% at 2 days after surgery had a higher incidence rate of low cardiac output syndrome, a longer duration of mechanical ventilation, a longer length of stay in the ICU, a longer length of hospital stay, and a higher mortality rate (P<0.05).

CONCLUSIONSInfants with fluid overload after surgery for congenital heart disease tend to develop AKI, and fluid overload may be associated with poor outcomes after surgery.