Objective: To explore the predictive value of intraoperative oxygen delivery (DO2) and renal regional oxygen saturation (rSO2 ) during cardiopulmonary bypass (CPB) for cardiac surgery-associated acute kidney injury (CS-AKI) in neonates with congenital heart disease (CHD).

Methods: A total of 235 neonates who underwent CPB-assisted cardiac surgery were enrolled and divided into CS-AKI and non-CS-AKI groups according to the occurrence of post operative CS-AKI. Perioperative clinical data, intraoperative DO2 and renal rSO2 as well as postoperative recovery indicators were collected. Binary logistic regression analysis was performed to screen independent risk factors for CS-AKI. Based on the independent predictors, a predictive nomogram was constructed and validated internally and externally. The predictive value of DO2 and rSO2 for CS-AKI was assessed. Results: Aortic cross-clamp (ACC) time, DO2 at 5 minutes post-ACC (T2), DO2 at 5 minutes after aortic opening (T3), the minimum renal rSO2 during CPB (R_min), and renal rSO2 at CPB termination (R_post) were independent influencing factors for CS-AKI. The combined application of the above four DO2 and rSO2 indicators yielded the optimal predictive efficacy for CS-AKI, with an (AUC) of 0.924. The constructed nomogram exhibited good discriminatory power, and external validation confirmed its excellent predictive efficiency.

Conclusion: ACC time, DO2 (T2, T3) and renal rSO2 (R_min, R_post) were independent determinants of CS-AKI in CHD neonates. The nomogram established based on these intraoperative oxygenation indices achieved superior predictive performance for postoperative CS-AKI.