BACKGROUND

Near-infrared spectroscopy (NIRS) is an emerging tool to identify signs of inadequate tissue oxygenation in preterm neonates with acute kidney injury (AKI). Previous studies have shown a correlation between low renal tissue oxygenation (RrSO) in the first 24 hours of age and the later development of AKI. In this prospective clinical trial, NIRS monitoring was used to identify changes in RrSO in comparison to traditional AKI markers, serum creatinine (SCr), and urine output (UOP).

METHODS

We enrolled 35 preterm neonates born less than 32 weeks' gestation and applied neonatal NIRS sensors at less than 48 hours of age. Neonates underwent 7 days of continuous monitoring. Renal and demographic information were collected for the first 7 days of age. AKI was determined by the modified neonatal Kidney Disease: Improving Global Outcomes (KDIGO) definition including UOP.

RESULTS

Three patients experienced AKI, all based on both SCr and UOP criteria. Each neonate with AKI had decreases in RrSO over 48 hours prior to changes in SCr and UOP. Patients with AKI had lower median RrSO values compared to patients without AKI over the first week of age, (32.4% vs. 60%, p < 0.001).

CONCLUSION

RrSO monitoring identified preterm neonates at risk for AKI. NIRS detected a decline in RrSO prior to changes in SCr and UOP and was significantly lower in patients with AKI compared to those without AKI. Further studies are needed to evaluate the ability of RrSO monitoring to detect signs of kidney stress prior to the diagnosis of AKI. Graphical abstract.