ABSTRACT
What Is Oliguria? Oliguria is defined as acute onset of decreased urine output less than 0.5 ml/kg/h or 400 ml/24 h in an adult. The context of the development of oliguria in the surgical patient is as important as the recognition of the event, as there is a broad spectrum of possible hemodynamic, mechanical, and toxin-related etiologies and early, appropriate intervention may mitigate progression from low urine output to acute renal failure (ARF). It should be acknowledged that the development of oliguria does not necessarily signal the beginning of irreversible renal failure; conversely, compromised renal function as measured by the kidneys ability to clear solute can be present in the setting of brisk urine output. Accordingly, the other major component of assessing potentially compromised renal function involves examining the metabolic clearance of the kidney by measuring nitrogen metabolism waste products, namely, urea and creatinine.
