The use of near-infrared spectroscopy to measure kidney oxygenation in the neonatal intensive care unit.

Near-infrared spectroscopy (NIRS) is a relatively recent technology, first applied in clinical contexts in the early 1970s. Critically ill neonates in the intensive care unit face unique post-natal adaptations that can be challenging when compounded by clinical co-morbidities. Given the size and limited blood volume of these patients, there is a need for non-invasive monitoring methods that go beyond traditional vital signs and laboratory assessments. NIRS offers a potential approach for monitoring regional tissue oxygenation and perfusion of the kidney with a potential for early detection of acute kidney injury in high-risk neonates. However, its application is not without challenges, including inconsistent normative values, technological and technique-related limitations, and uncertainties about its clinical applicability. Despite these challenges, NIRS monitoring of kidney oxygenation shows promise for supporting kidney health and informing clinical care decisions. In this educational review, we aim to outline the basic principles of NIRS as it relates to kidney oxygenation, summarize the current literature on its use for monitoring and clinical decision-making, discuss its limitations and knowledge gaps, and propose investigative approaches with future research directions.