Factors associated with acute kidney injury or failure in children undergoing cardiopulmonary bypass: a case-controlled study

Acute kidney injury (AKI) is a serious complication that occurs commonly following cardiopulmonary bypass (CPB) in infants and children. Underlying risk factors for AKI remain unclear, given changes in CPB practices during recent years. This retrospective, case–control study examined the relationships between patient, perioperative factors, AKI, and kidney failure in children who underwent CPB.

Methods: Cohorts of children with and without AKI were identified from the cardiac perfusion and nephrology consult databases. Demographic, perioperative, and postoperative outcome data were extracted from the databases and from medical records. Children were stratified into groups based on the Acute Dialysis Quality Initiative’s RIFLE definitions for acute kidney risk or injury (AKI-RI) and kidney failure.

Results: The study groups included 308 controls (no AKI-RI or failure), 161 with AKI-RI, and 89 with failure. Young age, preoperative need for mechanical ventilation, milrinone, or gentamicin; intraoperative use of milrinone and furosemide; durations of CPB and anesthesia; multiple cross-clamp and transfusion of blood products were significantly associated with AKI or failure. Young age, perioperative use of milrinone, multiple cross-clamps, extracorporeal membrane oxygenation, cardiac failure, neurological complications, sepsis, and failure significantly increased the odds of mortality.

Conclusion: This study identified multiple perioperative risk factors for AKI-RI, failure, and mortality in children undergoing CPB. In addition to commonly known risk factors, perioperative use of milrinone, particularly in young infants, and furosemide were independently predictive of poor renal outcomes in this sample. Findings suggest a need for the development of protocols aimed at renal protection in specific at risk patients.