Oxygen Delivery During Cardiopulmonary Bypass in Pediatric Patients With Congenital Heart Disease: Association With Postoperative Acute Kidney Injury

Objective: This study was designed to investigate the distribution of nadir oxygen delivery (DO₂), mean DO₂, and area under ideal DO₂ (AUiDO₂) among categorized age groups of pediatric patients and their associations with postoperative cardiac surgery–associated (CSA) acute kidney injury (AKI) and clinical outcomes. Design: Retrospective cohort study. Setting: A tertiary teaching hospital. Participants: Patients aged <15 years with congenital heart disease who underwent cardiac surgery between May 2018 and May 2022. Interventions: None. Measurements and Main Results: Nadir DO₂, mean DO₂, and AUiDO₂ were defined as the lowest DO₂, average DO₂, and dose of decrement combining the intensity and duration of DO₂ less than the calculated ideal DO₂, respectively. The primary outcome was CSA-AKI occurrence within 48 hours postoperatively. Secondary outcomes included maximum serum lactate levels (Lac_max) for the first 24 hours after pediatric cardiac intensive care unit admission. Of 479 patients, 147 (30.7%) developed AKI. Nadir DO₂ and AUiDO₂ were not significantly different between patients with CSA-AKI and those without CSA-AKI (p = 0.115 and p = 0.12, respectively). However, the mean DO₂ was significantly higher in patients with CSA-AKI (p = 0.025). After adjusting for potential confounders, no significant differences were observed in the odds for CSA-AKI based on increments in nadir DO₂, mean DO₂, or AUiDO₂. In contrast, nadir DO₂ and mean DO₂ were significantly associated with Lac_max in both univariate and multivariable regression analyses. Conclusion: DO₂-related values during cardiopulmonary bypass were not associated with CSA-AKI in pediatric patients with congenital heart disease. However, nadir DO₂ and mean DO₂ were significantly associated with postoperative serum lactate levels.