Urinary concentrating ability, assessed by urea urinary excretion, as early biomarker of Acute Kidney Injury

Abstract

Acute Kidney Injury (AKI) increases patients morbi-mortality in intensive care units, being the diagnosis based on urinary output and serum creatinine. Urinary volume may be influenced by interfering factors, as diuretic medications or hormones, like vasopressin; and serum creatinine, besides external interference, does not provide timely AKI diagnosis, once it raises just after 24 to 48h from initial insult. New biomarkers have been studied as possibilities of earlier AKI diagnosis, but most of them have still not been available in most clinical centers. Urinary concentration ability is one of the first parameters to change in chronic kidney disease progression, and it may be a marker of renal recovery for hemodialysis weaning in critically ill patients with acute kidney injury. Thus, the present study objectives to evaluate if urinary concentration ability, as accessed by urinary urea excretion, might be a timely biomarker, widely available in most of clinical settings, in AKI diagnosis. (AU)