Wiersema R, Kaufmann T, van der Veen HN, et al. - Researchers evaluated the diagnostic accuracy of Renal Resistive Index (RRI) and Venous Impedance Index (VII) for Acute Kidney Injury (AKI). They obtained measurements of RRI and VII among acutely admitted adult intensive care patients within 24 h of admission, in the prospective Simple Intensive Care Studies-II. Persistent AKI (non-resolved AKI on day three) was considered as the primary outcome. This study involved 371 patients, of those, 123 (33%) suffered from persistent AKI. A moderate specificity and low sensitivity of RRI and a high sensitivity and low specificity of VII was reported for persistent AKI. Overall, in this sample of acutely admitted critically ill patients, those with and without AKI did not differ in terms of measures of renal perfusion by renal ultrasound, and these measures were shown to have limited diagnostic accuracy for AKI.