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

Abstract

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 (RrSO2) in the first 24hours of age and the later development of AKI. In this prospective clinical trial, NIRS monitoring was used to identify changes in RrSO2 in comparison to traditional AKI markers, serum creatinine (SCr), and urine output (UOP). We enrolled 35 preterm neonates born less than 32weeks' gestation and applied neonatal NIRS sensors at less than 48hours of age. Neonates underwent 7days of continuous monitoring. Renal and demographic information were collected for the first 7days of age. AKI was determined by the modified neonatal Kidney Disease: Improving Global Outcomes (KDIGO) definition including UOP. Three patients experienced AKI, all based on both SCr and UOP criteria. Each neonate with AKI had decreases in RrSO2 over 48hours prior to changes in SCr and UOP. Patients with AKI had lower median RrSO2 values compared to patients without AKI over the first week of age, (32.4% vs. 60%, p < 0.001). RrSO2 monitoring identified preterm neonates at risk for AKI. NIRS detected a decline in RrSO2 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 RrSO2 monitoring to detect signs of kidney stress prior to the diagnosis of AKI. Graphical abstract.