To investigate cerebral autoregulation impairment during neonatal cardiac surgery.

A retrospective observational study.

Single-center, university teaching children’s hospital.

Neonates undergoing surgery for critical congenital heart defects.

Calculation of the cerebral oximetry index (COx) and COx-derived parameters was performed by processing signals from intraoperative routine monitoring.

High-resolution intraoperative data were retrieved from a cohort of 16 term neonates. COx was calculated as the linear correlation between mean arterial blood pressure and cerebral oximetry in a 5-minute moving time window. Averaged COx values were obtained before, during, and after cardiopulmonary bypass (CPB), and comparisons were made using the Kruskal-Wallis test. A linear mixed-effects model was used to examine the associations between COx and other intraoperative physiological variables. Intraoperative limits of autoregulation for a COx cut-off of 0.3 were identified by combining data from the entire cohort. The median COx was 0.02 (interquartile range [IQR], -0.08 to 0.13) pre-CPB, 0.34 (IQR, 0.18-0.43) during CPB, and 0.26 (IQR, 0.05-0.38) post-CPB. Intraoperative evolution of COx was linearly associated with changes in cerebral oximetry, pO₂, and core temperature but not with mean arterial pressure and pCO₂. For the entire cohort, the intraoperative lower and upper limits of autoregulation were 35 mmHg and 59 mmHg, respectively.

Cerebral autoregulation was impaired during CPB and remained altered after separation from bypass. Real-time monitoring of the COx may be useful for identifying autoregulation disturbances and providing a more individualized approach to CPB management.