Regional Cerebral Oxygen Saturation and Estimated Oxygen Extraction Ratio as Predictive Markers of Major Adverse Events in Pediatric Cardiac Patients

Regional cerebral oxygen saturation (ScO 2 ) determined by near-infrared spectroscopy, monitoring both arterial and venous blood oxygenation of the brain, could reflect the balance between oxygen delivery and consumption. The aim of this study was to determine the predictabilities of ScO 2 and estimated oxygen extraction ratio (eO 2 ER) with outcomes in pediatric patients with congenital heart disease (CHD). This study was a two-center, retrospective study of patients at 12 months of age or younger with CHD who underwent cardiac surgery. The primary outcome was a composite of one or more major adverse events (MAEs) after surgery: death from any cause, circulatory collapse that needed cardiopulmonary resuscitation, and requirement for extracorporeal membrane oxygenation. Based on the assumptions of arterial to venous blood ratio, eO 2 ER was calculated. A total of 647 cases were included in this study. MAEs occurred in 16 patients (2.5%). There were significant differences in the average post-bypass ScO 2 [46.61 (40.90, 52.05) vs. 58.52 (51.52, 66.08), p < 0.001] and the average post-bypass eO 2 ER [0.66 (0.60, 0.78) vs. 0.52 (0.43, 0.61), p < 0.001] between patients with MAEs and patients without MAEs. Area under the receiver operating curve (AUROC) of the average of post-bypass ScO 2 was 0.818 (95% confidence interval: 0.747–0.889), AUROC of the average of post-bypass eO 2 ER was 0.783 (0.697–0.870) and AUROC of post-bypass maximum serum lactate level was 0.635 (0.525–0.746). Both ScO 2 and eO 2 ER, especially after weaning off bypass, are acceptable predictive markers for predicting MAEs after cardiac surgery in infants.