Objective:

To synthesize current evidence on NIRS-derived perioperative rScO2 in pediatric CHD surgery requiring CPB, focusing on rScO2 trajectories, definitions of cerebral desaturation, and associations with brain injury and neurodevelopmental outcomes.

Approach:

• Literature Search: A comprehensive but non-systematic literature search was conducted, focusing on studies published from January 2015 to October 2023, with selective inclusion of earlier foundational studies.
• Search Terms: Search terms included combinations of 'congenital heart disease', 'pediatric cardiac surgery', 'cardiopulmonary bypass', 'near-infrared spectroscopy', and related terms.

Key Findings:

• rScO2 typically increases during cooling/deep hypothermia but reaches nadirs during low-flow perfusion or circulatory arrest.
• Postoperative cerebral oxygenation levels and cumulative desaturation burden within the first 12–24 hours may correlate with adverse biomarkers and poorer cognitive performance.
• Definitions and thresholds for cerebral desaturation vary across studies.

Interpretation:

Perioperative rScO2 trends and desaturation burden may support neurological risk stratification and individualized physiological assessment.

Limitations:

• Available studies remain limited and conclusions are heterogeneous.
• Standardized metrics and multimodal monitoring strategies are needed.

Conclusion:

Further prospective studies with long-term neurodevelopmental endpoints are required to define actionable targets for rScO2 monitoring.