Cerebral and Somatic Oxygen Saturation in Neonates with Congenital Heart Disease before Surgery

Background: We investigated preoperative cerebral (ScO(2)) and abdominal (StO(2)) regional oxygen saturations according to cardiac diagnosis in neonates with critical CHD, their time trends, and the clinical and biochemical parameters associated with them. Methods: Thirty-seven neonates with a prenatal diagnosis of CHD were included. ScO(2) and StO(2) values were continuously evaluated using near-infrared spectroscopy. Measurements were obtained hourly before surgery. A linear mixed effects model was used to assess the effects of time and cardiac diagnosis on regional oxygenation and to explore the contributing factors. Results: Regional oxygenation differed according to cardiac diagnosis (p < 0.001). ScO(2) was lowest in the patients with severe atrioventricular valvar regurgitation (AVVR) (48.1 ± 8.0%). StO(2) tended to be lower than ScO(2), and both worsened gradually during the period between birth and surgery. There was also a significant interaction between cardiac diagnosis and time. The factors related to ScO(2) were hemoglobin and arterial saturation, whereas no factor was associated with StO(2). Conclusions: Preoperative ScO(2) and StO(2) in critical CHD differed according to cardiac diagnosis. ScO(2) in the patients with severe AVVR was very low, which may imply cerebral hypoxia. ScO(2) gradually decreased, suggesting that the longer the time to surgery, the higher the risk of hypoxic brain injury.