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

We investigated preoperative cerebral (ScO₂) and abdominal (StO₂) regional oxygen saturations according to cardiac diagnosis in neonates with critical CHD, their time trends, and the clinical and biochemical parameters associated with them.

Thirty-seven neonates with a prenatal diagnosis of CHD were included. ScO₂ and StO₂ 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.

Regional oxygenation differed according to cardiac diagnosis (p < 0.001). ScO₂ was lowest in the patients with severe atrioventricular valvar regurgitation (AVVR) (48.1 ± 8.0%). StO₂ tended to be lower than ScO₂, 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 ScO₂ were hemoglobin and arterial saturation, whereas no factor was associated with StO₂.

Preoperative ScO₂ and StO₂ in critical CHD differed according to cardiac diagnosis. ScO₂ in the patients with severe AVVR was very low, which may imply cerebral hypoxia. ScO₂ gradually decreased, suggesting that the longer the time to surgery, the higher the risk of hypoxic brain injury.