Non-invasive continuous renal tissue oxygenation monitoring to identify preterm neonates at risk for acute kidney injury

Abstract

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 2 ) in the first 24\xa0hours of age and the later development of AKI. In this prospective clinical trial, NIRS monitoring was used to identify changes in RrSO 2 in comparison to traditional AKI markers, serum creatinine (SCr), and urine output (UOP). Methods We enrolled 35 preterm neonates born less than 32\xa0weeks’ gestation and applied neonatal NIRS sensors at less than 48\xa0hours of age. Neonates underwent 7\xa0days of continuous monitoring. Renal and demographic information were collected for the first 7\xa0days 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 2 over 48\xa0hours prior to changes in SCr and UOP. Patients with AKI had lower median RrSO 2 values compared to patients without AKI over the first week of age, (32.4% vs. 60%, p \u2009<\u20090.001). Conclusion RrSO 2 monitoring identified preterm neonates at risk for AKI. NIRS detected a decline in RrSO 2 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 2 monitoring to detect signs of kidney stress prior to the diagnosis of AKI. Graphical abstract