Introduction Cardiac surgery-associated acute kidney injury (CSA-AKI) remains a serious complication. The ratio of the venous-arterial carbon dioxide partial pressure difference (Pv-aCO 2 ) to the arterial-venous oxygen content difference (Ca-vO 2 ) is an indicator of tissue perfusion and anaerobic metabolism. We aimed to assess whether peak Pv-aCO 2 /Ca-vO 2 during cardiopulmonary bypass (CPB) predicts CSA-AKI in pediatric patients with cyanotic congenital heart disease (CHD). Methods We retrospectively reviewed patients aged < 10 years with cyanotic CHD who underwent cardiac surgery with CPB between January 2019 and August 2024. Peak Pv-aCO 2 /Ca-vO 2 during CPB was analyzed for its association with CSA-AKI using multivariate logistic regression adjusted for age, weight, CPB duration, aortic cross-clamp (ACC) time, and red blood cell transfusion. Classification and regression tree (CART) analysis was conducted to develop a predictive model. Results This study included 191 patients (96 (50.3 %) males; median age: 196 days interquartile range (IQR), 55–474). CSA-AKI occurred in 65 patients (34.0 %). Peak Pv-aCO 2 /Ca-vO 2 was higher in the AKI group than in the non-AKI group (IQR, 4.8 3.9–7.5 vs 3.9 2.8–5.4 mmHg·dL/mL; p = 0.001) and was significantly associated with CSA-AKI (adjusted odds ratio: 1.14; 95% confidence interval: 1.04–1.27). A CART-derived predictive model included ACC time, peak Pv-aCO 2 /Ca-vO 2 , and weight. A Pv-aCO 2 /Ca-vO 2 cut-off of 4.0 mmHg·dL/mL yielded 36.9 % sensitivity, 96.0 % specificity, 82.8 % positive predictive value, and 75.9 % negative predictive value. Conclusions In pediatric cardiac surgery for cyanotic CHD, high Pv-aCO 2 /Ca-vO 2 predicts CSA-AKI. These findings highlight the potential role of Pv-aCO 2 /Ca-vO 2 monitoring during CPB in developing novel pediatric goal-directed perfusion strategies.
Fujishiro et al. (2026) studied this question.