Use of near-infrared spectroscopy to guide care in the cardiac ICU: actionable insight or just another costly monitor without impact? The affirmative position: unlocking the black box of tissue perfusion

PURPOSE OF REVIEW: The assessment of hemodynamic stability in the pediatric cardiac intensive care unit (PCICU) has historically relied on macro-hemodynamic parameters that often fail to reflect microcirculatory distress. This review analyzes the 'affirmative' evidence from 2024 to 2025 advocating for near-infrared spectroscopy (NIRS/rSO2) not merely as a trend monitor, but as a critical decision-support tool. RECENT FINDINGS: New data demonstrate that NIRS provides 'hemodynamic lead time', predicting low cardiac output syndrome (LCOS) up to 12 h before lactate elevation. In pediatric cardiac arrest, NIRS has emerged as a superior guide to resuscitation quality compared to end-tidal CO2, particularly in cyanotic physiology. Furthermore, renal NIRS has been validated as a sensitive biomarker for acute kidney injury (AKI) and a predictor of extubation failure via the 'renal steal' mechanism. SUMMARY: NIRS bridges the gap between systemic vital signs and tissue-level oxygenation. Its integration into goal-directed protocols for LCOS prediction, high-stakes resuscitation, and mechanical support surveillance offers actionable insights that improve survival and reduce morbidity, justifying its role as a standard of care.