Role of Renal Arterial Doppler in Early Detection of Acute Kidney Injury in Critically Ill Late Preterm Infants

Background: An acute kidney injury (AKI), a potentially fatal illness with a high death rate, high treatment costs, and poor outcomes, is more likely to affect late preterm newborns. Monitoring microcirculation parameters is the most important criteria in anticipating AKI. In order to evaluate renal perfusion at the bedside of critically ill late preterm infants in the intensive care unit, two Doppler-based metrics were proposed: the kidney resistive index (RI) and the pulsitility index (PI).
Objective: The aim was to determine the value of renal arterial Doppler in early recognition of acute kidney injury in critically ill preterm infants.
Methods: Seventy-five late preterm newborns who were admitted to the neonatal critical care unit at AlZahraa Hospital University from January 2023 to January 2024 participated in this observational case control research. This study was done for a period of 1 year. Every case under study went through history taking, physical examination, Laboratory investigations (CBC, ABG, CRP, liver and kidney function) and Radiological investigation (renal Doppler at 3rd and 7th day of life).
Results: The RI and PI levels in the AKI group are increased by a significant amount at the 3rd day and at 7th days compared to the non-AKI group. The ideal cut-off value for RI to anticipate AKI is > 0.82 with sensitivity of 61.54%, specificity of 96.0% and AUC of 0.782 Also, The Receiver operating characteristic curve (ROC) shows that the PI can detect AKI at the cutoff point > 1.2 with sensitivity of 92.31%, specificity of 64.0% and AUC of 0.874.
 Conclusion: Renal Doppler assessment is feasible, noninvasive, bedside and promising tool in early identification of acute kidney impairment in extremely ill late-preterm infants.