Acute Kidney Injury in Infants Undergoing Cardiac Surgery Under Cardiopulmonary Bypass

Background Cardiac surgery-associated acute kidney injury (CS-AKI) is a significant complication associated with substantial morbidity and mortality. Infants are at a significant risk of developing this complication. There is a need to identify risk factors for CS-AKI in this population. This study aimed to assess the incidence, risk factors, and outcomes of CS-AKI, specifically in infants <1 year old undergoing cardiac surgery under cardiopulmonary bypass. Materials and Methods We conducted a prospective observational study at a single tertiary care center from September 2022 to September 2023. All infants <1 year old undergoing cardiac surgery under cardiopulmonary bypass were included. Data on preoperative, intraoperative, and postoperative factors were collected. The primary aim was to study the incidence of acute kidney injury (AKI) and fluid overload (FO). Secondary outcomes included the need for dialysis, length of intensive care unit (ICU) stay, and mortality. Results AKI was seen in 47 (33.6%) out of 140 infants. Cumulative fluid overload % in the overall cohort was -12% (-18% - -8%) [AKI group -18% (-33% to -15%) and non-AKI group -10% (-14% to -7%) p <0.001]. Significant AKI predictors included younger age, cyanotic heart disease, prolonged aortic cross-clamp (ACC) times ( p <0.001), sepsis ( p =0.002), and prolonged ventilation (>48 hours, p <0.001). Mortality was 2.9% (n=4); all deceased patients developed sepsis and required kidney replacement therapy (KRT). Multivariable analysis showed that cyanotic heart disease (OR 2.53, 95% CI: 1.06–6.00), prolonged ACC time (OR 3.78, 95% CI: 1.54–9.25), and prolonged ventilation (OR 6.01, 95% CI: 1.98–18.21) were independently associated with AKI. The length of ICU and hospital stay was significantly longer in infants with AKI ( p <0.001). Conclusion CS-AKI is common in infants, particularly those with cyanotic heart disease, prolonged surgery times, and sepsis. AKI is associated with higher morbidity, prolonged ICU stays, and increased mortality. Further research is needed to develop better predictive tools and early AKI biomarkers in this population, and strategies to reduce risk factors like prolonged ACC times and sepsis.